National 4/5 Biology
Unit 2 – Multicellular Organisms
Lesson 1 – Cells , tissues and organs

Learning Intentions
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To extend knowledge on multicellular organisms.
To develop knowledge on how cell structure is related to function.

Success Criteria
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I can state that multicellular organisms have more than one cell type and are made up of tissues and organs.
I can recognise that the structure of a cell is related to its function.
I can give examples of how cell structure is related to its function.

Multicellular organisms
 Can you think of any examples of multicellular organisms?

Multicellular organisms

What are multicellular organisms?
 Multicellular organisms have more than one cell type and are made up of tissues and organs.

Multicellular organisms cells tissues organs organisms

Multicellular organisms - cells
 Multicellular organisms are made up of many types of cell.
 Can you think of any cell types in the human body?

Cells in organs
 The cells in organs are specialised for their function.

What is the function of the following cells and why are they suited to their function?
Sperm cell
Red blood cell
Activity 1:
Collect a worksheet with the diagrams above.
Make notes on their structure and function in your jotter.
Root hair cell

Activity 2
 Use relevant resources to find out 3 more examples of cells where structure is related to function.
Cell type Structure Function

Activity 3 / extension
 Look at different cell types under the microscope and relate their structure and function

National 4/5 Biology
Unit 2 – Multicellular Organisms
Lesson 2 – Cells, tissues and organs

Learning Intentions
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To extend knowledge on multicellular organisms.
To develop knowledge on the formation of tissues from cells in multicellular organisms.
To develop knowledge on the formation of organs from tissues.

Success Criteria
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I can state tissues are made from groups of cells with similar structure and function.
I can give examples of how cells form tissues in multicellular organisms.
I can state that tissues form organs in multicellular organisms.
I can describe organ systems, recognising the cells, tissues and organs involved.

Multicellular organisms
 Can you remember what a multicellular organism is?
 Multicellular organisms have more than one cell type and are made up of tissues and organs.

Multicellular organisms cells tissues organs organisms

Multicellular organisms - tissues
 Tissues are made from groups of cells with similar structure and function.

Example 1 – nerve tissue
 Nerves carry impulses (e.g. sensation and motion) between the brain or spinal cord and other parts of the body.
Nervous tissue

 Nerve tissue is made up of nerve cells (neurons).
 The nervous system also contains glial cells which provide support and protection for neurons. They are essential for the proper operation of the nervous tissue and nervous system.

Nervous cells
Nervous tissue

Multicellular organisms cells tissues organs organisms

Multicellular organisms - organs
 Organs or organ systems are groups of tissues working together.
 Organs perform different functions.

 What do you think the organ system would be in the nerve cell example?
 The nervous system

Nervous cells
Nervous tissue
Nervous system

Activity 1
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Use the worksheet to construct this image in your jotter.
Add the appropriate labels.

 BBC Science & Nature - Human Body and Mind - Nervous System Layer

Example 2 – the circulatory system
 Activity 2: Use the worksheet to show the connection between the cells, tissues and organs in the circulatory system.

Tissues in the circulatory system
 What do you think the functions of the cardiac, nerve and blood tissues are in the circulatory system?

Tissues in the circulatory system
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The cardiac muscle tissue contracts, making the heart pump.
The nerve tissue brings messages that tell the heart how fast to beat.
The blood tissue is carried from the heart to other organs of the body.

Activity 3
Questions relating to the circulatory system activity
1) What is the function of red and white blood cells?
2) What do the words oxygenated and deoxygenated mean?
3) What are the functions of the valves in the heart diagram?
4) How many chambers does the heart have?
What are they called?

Activity 3 - answers
Answers relating to the circulatory system activity
1) What is the function of red and white blood cells?
Red blood cells transport oxygen around the body
- White blood cells are involved in the immune response to infection
2) What do the words oxygenated and deoxygenated mean?
Oxygenated – saturated with oxygen / high oxygen
- Deoxygenated – low oxygen

Activity 3 - answers
Answers relating to the circulatory system activity
3) What are the functions of the valves in the heart diagram?
Prevent the backflow of blood
4) How many chambers does the heart have? What are they called?
- 4
- Left ventricle, right ventricle, right atrium, left atrium

National 4/5 Biology
Unit 2 – Multicellular Organisms
Lesson 3 – Growth and development of organisms

Learning intentions
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To extend knowledge on growth
To explain the growth and development of a variety of animals

Success criteria
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I can state that growth is the irreversible increase in cell number which leads to an increase in mass or length.
I can compare the growth and development of a variety of animals.

What is growth?
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Growth is the irreversible increase in dry mass of an organism and is normally accompanied by an increase in cell number.
Growth involves the production of new structures.

Why is dry mass used and not fresh mass?
 Fresh mass is less reliable as an indicator of growth because there will be changes in an organisms water content which will affect their mass.

Activity - animal and plant development
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From the sheets choose two plants and two animals you would like to research.
Discuss the terms in the sheet as a class prior to starting the task.

National 4/5 Biology
Unit 2 – Multicellular Organisms
Lesson 4 – Seed germination

Learning intentions
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To extend knowledge on investigations
To extend knowledge on the conditions required for germination

Success criteria
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I can describe an experiment which shows that seeds need water for germination.
I can describe an experiment which shows that seeds need oxygen for germination.
I can describe an experiment which shows that seeds need warmth for germination.
I can describe an experiment which shows that seeds can germinate in the dark.

Recap questions
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What are the 3 parts of a seed?
What is germination?
What conditions do seeds need to germinate?
What does the word optimum mean?

Group task – What conditions do seeds need to germinate?
 The class will be split into groups to allow all investigations to be covered (temperature, oxygen, water and light)
 In your group you will plan an investigation on your chosen factor.
 Try and come up with a method on your own. (There are support sheets available if required).

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Your investigation and write up must include:
Aim: What variable factor are you investigating?
Hypothesis: What do you predict will happen?
Method/Diagram: brief description of what you are doing and how you will alter your variable factor
Results: Construct a table
Graph: Use your results
Conclusion: What did your results show?
Evaluation: How could you improve the experiment? Why is more than one seed used?
Why is only one variable factor investigated at one time?

National 4/5 Biology
Unit 2 – Multicellular Organisms
Lesson 5 – Conditions needed to maintain growth and development in humans

Learning intentions
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To explain what is needed by humans for growth and development.
To extend knowledge on the uses of food by the body.
To develop knowledge on metabolism.

Success criteria
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I can state that food is a source of fuel and building materials.
I can state that food helps fight disease.
I can identify the different food groups and their uses by the body.
I can explain what vitamins and minerals are needed for.
I can explain what water is used for in the body.
I can explain what is meant by metabolism.

Activity:
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Collect an information booklet – read through the information and answer the questions.
Do not lose these sheets – they are your notes and will be needed for revision.

Extension activity
 Research and present information on either a vitamin or mineral deficiency
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Points to think about:
What the vitamin/ mineral is needed for
Why someone may become deficient
The effect of the deficiency on the body
The effects on growth of deficiency in a diet

How do chemicals and radiation affect growth and development
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You have 30 minutes to find out ways in which radiation and chemicals can affect growth and development.
Present the information in your jotter e.g. spider diagram, table or note form.

Homework
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Produce a poster or piece of writing on commercial plant growing.
Think about what it is and why it is done.

National 4/5 Biology
Unit 2 – Multicellular Organisms
Lesson 6 – Stem cells

Learning intentions
 To extend knowledge on stem cells.

Success criteria
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I can state that stem cells are the site of production of specialised cells in animals.
I can state that stem cells are involved in growth and repair.

What are stem cells?
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Stem cells are the sites of production of specialised cells in animals.
They have the potential to become different types of cell.
They are involved in growth and repair.

Investigating stem cells
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Use a variety of media to investigate the potential uses of stem cells.
Think about what ethical issues are associated with their use.

National 4/5 Biology
Unit 2 – Multicellular Organisms
Lesson 7 – Meristems

Learning intentions
 To develop knowledge on meristems

Success criteria
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I can state that meristems are areas of non specialised cells in plants
I can state that meristems are involved in plant growth
I can state that meristems produce cells that can become specialised into any plant cell type
I can state that meristems are the only points in plants where cell division happens

What are meristems?
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Meristems are the sites of production of non-specialised cells in plants.
These cells have the potential to become any type of plant cell and contribute to plant growth.
They are the only sites for cell division in a plant.

Where are meristems found in the plant?
 Meristems are present at root and shoot tips (apical meristems) and lateral buds
(lateral meristems)
Collect a diagram and highlight the lateral and apical meristems.
Lateral buds

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Cells at root and shoot tips undergo rapid mitosis and cell division producing new cells
New cells expand by a process called
Xylem and elongation phloem
New cells produced can differentiate to form specialised tissues such as xylem or phloem
Differentiation
Elongation
Mitosis

Lateral meristems Xylem
Vascular
Bundle
Cambium
Phloem
• Lateral meristems consist of cambium cells .
• These cells are situated in vascular bundles between xylem and phloem tissue
Collect and label a diagram of the lateral meristem.

Secondary Thickening ( growth )
Xylem
Cambium
Phloem
Vascular Bundle

Rings of
Xylem
Year 1
Year 2
Year 3
Year 4
• Xylem is produced every year leading to the formation of annual rings

Poor year
Good year
Year 4
Year 3
Year 2
Year 1
Summer into autumn Xylem
Spring into summer Xylem
Cambium

Size of annual rings
• Spring into Summer – large thin walled xylem vessels allow for increased flow of water and minerals.
• Summer into Autumn – small thick walled xylem provide greater support.
• The width of each ring is dependent upon growing conditions present during that year.
a. Wider rings are produced by warm or wet weather b. Narrow rings are produced by cold or dry conditions.

National 5 Biology
Unit 2 – Multicellular Organisms
Lesson 1 – Sexual and asexual reproduction in plants and animals

Learning Intentions
 To develop knowledge on asexual and sexual reproduction in plants and animals.

Success Criteria
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I can explain sexual and asexual reproduction.
I can give examples of sexual and asexual reproduction in animals.
I can give examples of asexual and sexual reproduction in plants.

 Reproduction is the process of producing new individuals or offspring.
 It is essential to ensure a species continues to survive.
Living things reproduce by one of two methods
 Sexual reproduction
 Asexual reproduction

 This type of reproduction requires two parents who pass on genes in sex cells. These cells fuse together at fertilisation and develop into new offspring.
 This results in offspring with a mix of inherited characteristics.
 The parents are usually a female and a male, but not always.

There are two types of fertilisation:
Internal fertilisation
External fertilisation

 The eggs and sperm are deposited outside the body and the sperm moves towards the egg.
 This fertilisation is used by animals who reproduce in water.
e.g. fish, amphibians, crustaceans and molluscs

 The eggs and sperm meet inside the body.
 The male usually deposits the sperm inside the female.
 This type of fertilisation is used by animals who reproduce on land.
e.g. mammals, reptiles, birds, insects, spiders

 Fertilised eggs either develop inside or outside an animals body.
 Research the fertilisation and development of the following organisms.
Example of Animal Type of fertilisation Type of development mammal reptiles birds
Invertebrates
Amphibians
Fish
Parental care

Example of Animal Type of fertilisation Type of development mammal reptiles birds
Invertebrates
Amphibians
Fish internal internal internal internal external external internal external external external external external parental care yes no yes no no no

 These animals have both female and male sex organs
 They can change sex during their life from one gender into the next
 This resolves the problem of finding mates
Examples
Snails, clown fish, earth worms

 Sexual reproduction introduces new gene combinations into a population.
 A species is more likely to survive sudden changes in the environment because some individuals will have adaptations to the new conditions.

 Offspring are produced from only one parent.
 The offspring only inherit the genes of that one parent so there is no variation.
 It does not involve sex cells.
 The offspring will be an exact genetic copy of the parent.

 In animals there are 5 main methods that allow animals to reproduce asexually
 Budding
 Fragmentation
 Regeneration
 Parthenogenesis
 Binary fission

 Offspring grow out of or within the body of the parent e.g. Hydra, yeast, sponges

 The body of a parent can break into distinct pieces each of which can produce an offspring e.g. Planarian

 Piece of the parent can detach and it can grow into new individuals e.g. Starfish

 Development of an egg that has not been fertilised e.g. Shark, boa constrictor, stick insect, bee wasp, ant, whiptail lizard, komodo dragon

 Single cell replicates and divides into two identical cells e.g. bacteria

 No need to waste energy moving to find a mate
 Numerous offspring are produced without wasted energy and time

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They would all share a genetic weakness
If a stable environment changes then no individual would have the adaptations needed to survive

 There a two main methods that allow plants to reproduce sexually.
 Spores
 When Ferns and Bryophytes (moss and liver worts) reproduce they make spores from which a new plant grows .
 Seeds
 When flowering plants reproduce they make seeds from which a new plant grows.

• It introduces new gene combinations into a population.
• Increases variety of some characteristics.
• A species is more likely to survive sudden changes in the environment because some individuals will be able to survive.
• Produces seeds or spores that can stay dormant until conditions are suitable for growth.
• Plants are well distributed so less competition for resources between offspring e.g. water, light & space.

 This produces offspring that inherit genes from only one parent.
 This results in offspring genetically identical to the parents.
 In plants this type of reproduction is a also called vegetative propagation.

 There are three main methods that allow plants to reproduce asexually.
 Runners
 Bulbs
 Tubers

Runners are side stems which produce offspring at various points. The clones receive food from the parent until they are fully developed.

Tubers are underground stems swollen with food.
New plants grow from the tubers using the energy stored in the tuber in the form of starch.

Bulbs
 Bulbs are a leaf bases swollen with food.
 New plants grow from these using the stored food for energy for growth.

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Carry out various propagation techniques with various plants:
Seeds
Cuttings
Bulbs

Commercial uses of plants
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Research the commercial uses of plants.
Feedback to the class.
Use the feedback from everyone to create your own notes.

National 5 Biology
Unit 2 – Multicellular Organisms
Lesson 2 – Sexual Reproduction in detail

Learning Intentions
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To extend knowledge on reproduction
To develop knowledge on the terms diploid and haploid
To develop knowledge on the term gonads

Success Criteria
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I can state that body cells are diploid.
I can identify the gametes and the site of gamete production in plants and animals.
I can identify the term haploid.
I can explain how the fertilisation of haploid gametes produces a diploid zygote.

Body cells
 What do we mean by a body cell?
 A body cell is every cell in the body except from the sex cells .

Body cells
 How many chromosomes does a human body cell have?
 46

Body cells
 How many of each chromosome are present in the diagram?

Body cells
 There are 2 copies of each chromosome in every body cell (including 2 sex chromosomes).
 23 pairs of 2 = 46 chromosomes in every body cell that is produced.
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Body cells are known as diploid cells.
(Di = 2)

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Activity 1 - Chromosomes in organisms
Different numbers of organisms have different numbers of chromosomes.
Research the following organisms and complete the table.
Organism Number of chromosomes
Dog
Human
Donkey
Elephant
Rabbit
Snail
Cabbage

Chromosomes in organisms - answers
Organism
Dog
Human
Donkey
Elephant
Rabbit
Snail
Cabbage
62
56
44
24
18
Number of chromosomes
38
46

Sex cells
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Sex cells are known as gametes .
The gametes in animals are the sperm and the egg nucleus
Tail cytoplasm
Cell membrane

Activity 2
 Collect and label a diagram of the sperm and egg.

Gametes
 The cells that produce the gametes are known as gonads .
 Do you have any idea what the gonads are that produce the sperm and the egg?

Where are sperm made?
Sperm are made in the testes

Where are eggs made?
Eggs are made in the ovary

Activity 3
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Collect the diagrams of the male and female reproductive organs.
Highlight the parts where gamete production takes place.

Gamete formation in plants
• Flowers are the sexual organs of plants
• Both male and female reproductive organs are usually found on the same flower

Gamete formation in plants
•Male gonad = anther
•Male sex cell = pollen
• Female gonad = ovary
•Female sex cell = ovule containing the egg

Activity 4
 Collect and label the diagram of the flower.
 Highlight the male and female gonads and sex cells.

Activity 5 – flower dissection
Flower Dissection .pdf

Sex cells
 Earlier we learnt that normal body cells have
46 chromosomes and that they are diploid .
 Sex cells (gametes) only have 23 chromosomes and are said to be haploid.
 Why do you think gametes only have 23 chromosomes and not 46?

Why do gametes have 23 chromosomes?
 This is because the 23 chromosomes from both the sperm and egg fuse together during fertilisation to give a zygote with 46 chromosomes.

Egg with single set of chromosomes
23
Sperm with single set of chromosomes
23
Fusion of nuclei
46
Zygote with double set of chromosomes

National 5 Biology
Unit 2 – Multicellular organisms
Lesson 1 – Variation

Learning intentions
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To develop knowledge on inheritance
To develop knowledge on discrete and continuous variation.

Success criteria
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I know that combining genes from separate parents contributes to variation within a species
I can give examples of inherited characteristics
I can define and recognise discrete variation and give examples
I can define and recognise continuous variation and give examples

What is genetic variation?
 Genetic variation refers to the variety of genes in a population.
 Combining genes from separate parents contributes to variation within a species

What is genetic variation?
 Humans vary in numerous characteristics e.g. eye colour and hair colour because they have different genes.
 These genes are inherited from their parents.
 What other inherited characteristics can cause variation within populations?

Inherited characteristics
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Hair type
Hand size
Height
Petal colour
Coat colour
Dimples
Tongue rolling

Variation
 Variation can be categorised into two types:
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Discrete variation
Continuous variation

Discrete variation
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Discrete variation refers to differences in characteristics that have a defined form.
You can think of it as being either/or.
(E.g. Your earlobes are either attached or they are not. You can either roll your tongue or you cannot You either have brown hair or you do not).
Information is usually presented in a bar graph or pie chart.

10
Number in class 5 green blue brown grey
Eye colour

Activity 1 – as a class find out the number of people with each eye colour. Construct a bar graph of the results and answer the questions .
Eye colour
Blue
Brown
Green
Grey
Number of people
1. What percentage of people have blue eyes?
2. What is the ratio of brown eyes to grey eyes?
3. Write down 5 examples of discrete variation.

Continuous variation
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Continuous variation exists in a range of forms.
There are usually a variety of figures for the characteristic.
E.g. Height and temperature.
Information is usually presented in a line graph or histogram.

Number in Year
30
25
20
15
10
5
120-
124
125-
129
130-
134
135-
139
140-
144
145-
149
150-
154
155-
159
160-
164
Height in cm

Activity 2 – construct your own histogram using the heights from the people in your class
Number of people Height (cm)
120 -124
125-129
130-135
135-139
140-144
145-149
150-154
155-159
160-164

Activity 3 – construct a line graph of the following results and answer the questions.
Time (minutes)
0
5
10
Temperature (oC)
13
25
60
15
20
88
70
25 64
30 50
1. Explain the relationship between time and temperature
2. Calculate the percentage increase in temperature between 0 minutes and
15 minutes
3. Write down 5 examples of continuous variation.

National 5 Biology
Unit 2 – Multicellular organisms
Lesson 2 – Monohybrid cross

Learning intentions
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To develop knowledge on the monohybrid cross.
To develop knowledge on the terms associated with the monohybrid cross.

Success criteria
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I can explain and carry out a monohybrid cross.
I can define the terms allele, phenotype, genotype, dominant, recessive, true breeding, homozygous and heterozygous.

Genetics
 The way in which inherited characteristics are passed on from parents to their offspring follows a pattern.
 The study of patterns of inheritance is called
GENETICS

Chromosomes
Genetic information passed on from parents to offspring is carried on structures called chromosomes which are found in the nucleus.
Chromosomes are usually only visible during cell division when stained with a dye.

Genes and Alleles
Genes are part of chromosomes.
Each gene can exist in a number of different forms.
E.g. the gene for eye colour can be for brown or blue or green or grey etc.
The different forms of each gene are known as
ALLELES.

Collect a copy of the diagram and add it to your notes

Organism
Human
Labrador Dog
Cat
Budgerigar
Cattle
Pea Plant
Maize
Gene
Blood group
Coat Colour
Hair Length
Feather Colour
Horns
Height
Grain Colour
Examples of
Alleles
A and B etc
Black, Golden
Short, Long
Blue , Green
Horns, Hornless
Tall, Dwarf
Yellow, Purple

Genotype
• The type of genes that an organism possesses is called its GENOTYPE.

Phenotype
The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Some characteristics and their phenotypes
Organism Characteristic
Body Colour
Fruit Fly
Guinea Pig
Peas
Wing Type
Hair Colour
Hair Type
Stem Length
Flower Colour
Phenotype
Grey
Black
Straight
Curled
White
Black
Smooth
Rough
Dwarf
Tall
Red
White

Dominance
Some phenotypes are dominant to others. It is these characteristics you see even if others are present e.g. black hair is dominant to red hair .
+ =
The characteristic you do not see e.g. red hair would be called recessive.

True-breeding
A true-breeding organism can be crossed with another organism of the same kind and produce off-spring with exactly the same characteristic phenotypes.
+ =
True breeding individuals have only one type of allele

A homozygous individual possesses two of the same kinds of alleles e.g. TT or tt (true breeding)
A heterozygous individual possesses two different alleles e.g. Tt

Examples of phenotype, genotype, dominant and recessive
The b and B represent alleles.
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Why is there two alleles present?
Why is the letter b or B used?
What phenotype would a person with Bb have?

Monohybrid cross
 A cross between two parents different in their phenotypes for one characteristic is called a monohybrid cross.
Most characteristics that are controlled by a single gene show discontinuous variation – there are clear-cut phenotypes e.g. tongue rolling, lilac or white flowers in pea plants

P
Represents the parents
F
1
Represents the first generation
F
2
Represents the second generation

A lot of important work in genetics has been done by studying inheritance in fruit flies.

One characteristic which can be used to illustrate inheritance is wing type in Fruit Flies.
These can be NORMAL or VESTIGIAL.
Normal wings

Fruit fly with normal wings
Fruit fly with vestigial wings

Wing type is controlled by a pair of genes.
Each gene can be one of two types of ALLELES .
N = normal wings n = vestigial wings
Normal wing is dominant over vestigial wing.
Vestigial wing is said to be recessive .

Parent (P)
Gametes
NN X nn
N n
F1 generation All
Nn
Genotype all Nn
Phenotype all Normal winged

F1 generation
Gametes
Nn
N or n
X Nn
N or n
We can work out the chances of each type of offspring using a punnett square.
N n
N n
NN Nn
Nn nn

F2
Generation N n
N n
NN Nn
Genotypes NN , Nn and nn
Phenotypes Normal and Vestigial
Phenotype Ratio 3:1

Activity 1
 Use the information you have learned so far to complete the stages of the monohybrid cross on the next slide.

Parent genotype
Gametes
F1 generation
Cross F1
Gametes
Punnett square
F2 generation
(genotypes)
F2 generation
(phenotypes)
Ratio
Black mouse x
White mouse

Observed vs. predicted phenotypic ratios
•Monohybrid crosses always produce a 3:1 ratio in the
F
2 generation. However, there is often a difference between the observed and predicted figures.
•This happens because fertilisation is a random process involving chance .

F
2
Ratios by Experiment
Investigator Number of
Yellow Seeds
Number of
Green seeds
Mendel
Correns
Tschermak
Hurst
Bateson
Lock
Darbishire
TOTALS
6022
1394
3580
1310
11902
1438
109060
134706
2001
453
1190
445
3903
514
36186
44692
Total
8023
1847
4770
1755
15806
1952
145246
179246
Ratio
3.01 : 1
3.08 : 1
3.01 : 1
2.94 : 1
3.05 : 1
2.80 : 1
3.01 : 1
3.01:1

Activity 2
 Complete the monohybrid cross worksheet.

National 5 Biology
Unit 2 – Multicellular organisms
Lesson 3 – polygenic inheritance and family trees

Learning intentions
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To develop knowledge on polygenic inheritance.
To develop understanding on family trees and the benefits they have.

Success criteria
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I can define the term polygenic inheritance and give examples.
I can use a family tree to work out the phenotypes and genotypes of individuals.
I know that individuals with medical traits can receive genetic counselling.

Polygenic inheritance
 Most features of an individual phenotype are polygenic and show continuous variation.
 Polygenic inheritance is when a single trait is controlled by two or more sets of alleles.

Example – skin colour
 Many different alleles exist for each parent therefore numerous skin colours can be visible in the next generation.

Example – skin colour
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What are the possible genotypes of the F2 generation? (you do not need to write down them all)
Each of these genotypes produces a slightly different skin colour

Collect a copy of the diagrams showing skin colour inheritance

Family trees
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What is a family tree?
A family tree is a diagram showing the relationships between people in several generations of a family.

Activity 1
 Can you make a family tree for your own family?

Genetic conditions
 Family trees can be used to identify individuals with a genetic condition.
 A genetic condition is an illness caused by abnormalities in genes or chromosomes.

Examples of genetic disorders
 Colour blindness - the inability or decreased ability to see colour , or perceive colour differences, under normal lighting conditions.
 Cystic fibrosis -affects the lungs and also the pancreas , liver , and intestine . It is characterised by abnormal transport of chloride and sodium across an epithelium , leading to thick, viscous secretions.

Examples of genetic disorders
 Haemophilia - a group of genetic disorders that impair the body's ability to control blood clotting.
 Tay –Sachs disease a rare genetic disorder . It causes a progressive deterioration of mental and physical abilities that starts around six months of age and usually results in death by the age of four.

How are the defected genes passed on?
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The mother and the father in this family are both carriers for a genetic condition.
This means that they have one defective copy of the gene and one normal copy.
They do not have the condition because the normal gene (in this case) is dominant over the defective one.

Family tree
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Family trees can be used to identify individuals with a condition within a family.
It allows families to see the risk that any future children have of having the condition.

Activity 2 - Using a family tree
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Imagine this was a family tree for colour blindness.
An affected individual has the genotype bb and a normal individual has the genotype BB.
Work out the genotypes and phenotypes for the members of the family.

Genetic counselling
 Genetic counselling is the process by which patients or relatives, at risk of an inherited disorder, are advised of the consequences and nature of the disorder, the probability of developing or transmitting it, and the options open to them in management and family planning.

Activity 3 – research (extension)
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Choose a genetic condition
Prepare a powerpoint presentation on the condition.
Include key aspects:
What is the condition
What causes it
How is it treated
Is it dominant or recessive

National 4/5 Biology
Unit 2 – Multicellular Organisms
Lesson 1 – Nervous control

Learning Intentions
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To extend knowledge on nervous control.
To develop knowledge on the brain structure.

Success Criteria
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I can state that the nervous system is made of the brain, spinal cord and nerves
I can state that the Central Nervous System
(CNS) is made of the brain and spinal cord
I know the functions of the cerebrum, cerebellum and medulla
I know how information flows around the body in sensory nerves, motor nerves and relay nerves
I know that a synapse is a join between neurones (nerve cells)

Communication
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Internal communication is required for survival of a multicellular organism.
Cells in multicellular organisms do not work independently.

Co-ordination
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Co-ordination in the body involves the sense organs gathering information (1),
It involves the Central nervous system (2) and the muscles (3). These must work together efficiently to bring about all the many functions essential to life.

Human nervous system
The human nervous system is composed of three parts: the brain, spinal cord and the nerves.
The Central Nervous
System (CNS) is the brain and spinal cord

Nerves
Nerves carry information from the senses to the central nervous system and from the central nervous system to the muscles
Collect and stick in the diagram.

The nervous system is composed of two parts: the central nervous system and the peripheral nervous system.

Central nervous system
The central nervous system
( CNS ) sorts out information from the senses and sends messages to those muscles which make the appropriate response.
The CNS is composed of the brain and the spinal chord.

Peripheral Nervous System
This is composed of the sensory nerves and the motor nerves which take and send messages from the body.
It is electrical impulses that move along the neurons.

Sensory nerves
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Receptors on the skin detect stimuli.
Sensory nerves then send messages to the brain from the sense organs.

Motor Neurones
Motor neurones connect the brain to the body.
Messages are sent from the brain to the muscles where a response happens.

Stimuli Receptors Sensory nerves
CNS Motor nerves Response
Response can be a rapid action from a muscle or a slower response from a gland.

Synapse
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A join between two nerves is known as a synapse .
It allows chemicals to transfer from one neuron to another.

Reflex Arc
1)
2)
3)
The body responds immediately to a stimulus without intervention from the brain.
The sensory nerve sends message to the spinal cord
The impulse passes through a relay neurone
The impulse is picked up by a motor neurone which transmits the signal to the muscles.

A reflex arc

Reflex actions
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These are rapid, involuntary and automatic
Conscious thought from the brain is not required
They protect the body from harm
They may still work for a short time after an animal has died
* Discuss human reflexes e.g. knee jerk.

Brain
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The brain is a bundle of nerve fibres segregated into several different regions:
Cerebrum – responsible for memory, reasoning, imagination and conscious thought
Cerebellum – balance and co-ordination
Medulla – rate of breathing and heartbeat
Collect and label the brain diagram

Activity
 Complete the worksheet on terms relating to the nervous system