BIOLOGY-­‐SC 9
NAME: LESSON 1: ANIMAL AND PLANT CELL ANIMAL CELLS Animal cells are equipped with structures, called ___________________, that allow the cell to perform a __________________________________. Table of Cell Organelles with their Functions: ORGANELLE cell membrane FUNCTION cytoplasm Mitochondria Ribosome Endoplasmic Reticulum Vesicles Golgi body Vacuoles Lysosome Centriole THE NUCLEUS Table of the Nucleus and the Nuclear Organelle Functions Nucleus Nucleolus Nuclear membrane Nuclear pores PLANT CELLS Plant cells are equipped with 3 structures that animal cells do not have. •
________________________ -­‐ trap energy from Sun to make glucose, food for the plant •
________________________ -­‐ tough, rigid structure that surrounds cell membrane, provides protection and structural support •
_______________________ -­‐ plant cells are equipped with a large vacuole for storing water YOUR TASK TODAY: THE EDIBLE CELL PROJECT •
You will work with a partner or in a group of 3 to make an edible cell (see photo) •
As a class we will make a rubric to decide what the edible cell should be graded on (a max of 5 criteria) •
You will brainstorm with your partner/group how you will go about making an edible cell •
Example: what edible products will you use for each organelle •
Example: how will you make a key to describe what everything is LESSON 2: THE NUCLEUS AND DNA •
The nucleus contains _______________________________________ •
DNA has the master set of instructions for __________________________, what _______________ and ____________________________ DNA STRUCTURE •
DNA looks like a ________________________ – two strands wrap around each other in a ___________ •
DNA is often called a __________________________ •
The sides of the DNA ladder are made of ______________ and __________________ (known as a ________________________________________) •
•
The steps of the ladder are made of nitrogenous bases: •
_____________________ (A) •
_____________________ (G) •
_____________________ (C) •
_____________________ (T). The bases join in a specific way •
___ always joins with ___ with ____ Hydrogen bonds •
___ always joins with ___ with ___ Hydrogen bonds MAKE A DNA MODEL-­‐PIPE CLEANER METHOD Supplies: You will need 6 colors of pipe cleaners, one for each of the following-­‐ sugar, phosphate, adenine, thymine, cytosine, and guanine •
Use one color pipe cleaner to make two sugar backbones, add in a different color of small phosphates to your backbone •
Use 4 different colors of pipe cleaners to make the 4 bases and connect them A-­‐T and C-­‐G to the backbone •
Twist your DNA model into a double helix •
Make a key so you know which color corresponds to which part of the DNA molecule and note how many hydrogen bonds are involved in that bond LESSON 3: DNA à GENES à CHROMOSOMES WHAT IS A GENE? •
Genes are ________________________________located on a _________________ •
Genes can be _________________________________________________________ •
Genes store the information needed to produce ______________ DNA CONDENSES INTO CHROMATIN •
_______________________________ into ____________________ •
Chromatin= _____________ + ________________ •
When the cell is ‘working’ the __________________________ so that it can produce _____________ •
When the cell is ‘replicating’ or ‘dividing’ the ___________________________ into very compact _____________________________ DNA à CHROMOSOMES •
Most of the time DNA is in the form of ____________________ •
Chromatin coils tightly into __________________________________________________________ •
Each chromosomes is made up of _____________________________________________________ THE HUMAN KARYOTYPE How many chromosomes do humans have? _______ How many pairs are there? ______ What are the sex chromosomes? ___________ What makes a person male or female? ______________________________ Why are the chromosomes banded and why do they look different? LETS PUT IT ALL TOGETHER….. -­‐DNA twists into chromatin -­‐Chromatin is DNA and protein -­‐Chromatin twists into chromosomes -­‐Genes are small segments of bases on the chromosome -­‐Chromosomes are contained In the nucleus of the cell ____________________________ Trisomy 21-­‐______________________________: Extra copy of _____________________________________ Symptoms Include: a flattened nose, protruding tongue, upward slanting eyes, short hands and fingers, and a single crease in the palm Trisomy 13-­‐ _____________________________: Extra copy of chromos______________________________ Symptoms Include: -­‐polydactyly, low set ears,microcephaly, small eyes, absent or malformed nose, cleft lip and palate Trisomy 18-­‐ _______________________________: Extra copy of ___________________________________ Symptoms include: VSD heart defect, kidney defects, Rocker bottom feet, low set ears, Strawberry shaped head, Clenched hands __________________ Syndrome-­‐ 45, X Symptoms: web neck, abnormal bone development, short stature, no periods, sterile Translocations-­‐ chromosomes swap genetic material Deletions-­‐ a missing chunk of chromosome Duplication-­‐ a duplicated portion of genetic material Isochromosome-­‐ a deletion and a duplication LESSON 4: 9 STEPS TO PROTEIN PRODUCTION Step 1: The _________________ receives a __________________________ to make a ____________________ Step 2: The __________________________________________ is copied into a small molecule called _________. Step 3: __________________________________________ through a __________________________. Step 4: The RNA message is _________________________________________, the ribosome makes _________ Step 5: The manufactured protein ________________________________________________________ (ER). Step 6: A ___________________________________________________, and carries the protein to the __________________ Step 7: The Golgi body _____________________________________________ for transport out of the cell Step 8: A ____________________________________________________________ to carry the protein to the ________________________________ Step 9: The vesicle ___________________________________________, and its protein contents are __________________________________ ACTIVITY: COMIC STRIP OF PROTEIN PRODUCTION -­‐Using the knowledge of the 9 steps of how to make a protein create a comic strip of the events in a creative and interesting way -­‐You should have a minimum of 9 squares in your comic -­‐Your comic must fully demonstrate your knowledge of protein production -­‐Use you imagination and have fun! LESSON 5: MUTATIONS A gene ______________ involves a change in the ______________________ (A,C,T,G) that make up the gene. -­‐ Remember our DNA structure…4 bases with a sugar-­‐phosphate backbone 3 TYPES OF MUTATIONS 1) DELETION MUTATION -­‐ __________________________________________________________________ -­‐when this happens there is a shift in the DNA causing everything after the mutation to be changed (frame shift) 2) ADDITION MUTATION -­‐ ______________________________________________________________ -­‐an addition mutation also causes all DNA after the mutation to be changed in a frame shift mutation 3) SUBSTITUTION MUTATION (________________________________________________) -­‐This type of mutation is a point mutation and does not cause a frame shift -­‐In this photo a guanine (G)was mutated to become an adenine (A) causing a C282Ymutation which causes Hemochromatosis THE 3 EFFECTS OF MUTATIONS •
•
•
1) ________________________ •
When a gene mutation benefits the individual. •
Example: some people are now immune to HIV because they had a mutation that prevents the cell receptors for HIV 2) ________________________ •
When a gene mutation harms the individual •
Example: Sickle cell genes in affected humans cause blood cells that are abnormally shaped. 3) ________________________ •
When a gene mutation has no effect on the individual •
Example: The white Kermode bear. One base pair mutation in the gene for coat color. WHAT CAUSES MUTATIONS? •
So what causes all these mutations? ______________________. •
Mutagens are substances or factors that cause mutations •
Examples: Environmental mutagens such as mercury, cigarette smoke, X-­‐ray and UV radiation, and certain viruses can cause mutations LESSON 6: THE CELL CYCLE AND MITOSIS B. _______________________ •
Hatchlings are born with specialized teeth for peeling and eating skin •
The mother’s skin is thick and rich in fat •
Hatchlings feed off their mother’s skin for up to 4 weeks whereby she loses 14% of her body weight •
New skin cells must grow to replace the ones eaten…this is called cell division The life of a cell is divided into 3 stages known as the cell cycle: •
Interphase: __________________________________________________________________________ •
Mitosis: _____________________________________________________________________________ •
Cytokinesis: _________________________________________________________________________ INTERPHASE •
The cells spend the majority of their lives in interphase in which the cell is undergoing various functions (Ex: releasing digestive enzymes in the stomach cells) •
There are 3 phases of interphase: •
1 ___________________ •
2 ___________________ •
3 _______________________________ INTERPHASE PHASE 1: GROWTH AND PREPARATION •
_____________________________ •
cell makes proteins and molecules needed for the cell to function •
_____________________________ INTERPHASE STEP 2: DNA REPLICATION 1. _________________________________________ 2. _________________________________________ 3. Two new identical DNA molecules are produced The cell temporarily has 2 complete sets of DNA. Enzymes control this process (DNA Polymerase, DNA Ligase) INTERPHASE PHASE 3: CONTINUED GROWTH AND PREPARATION -­‐ after DNA replication the cell continues to grow -­‐ _________________________________________________ Remember protein production? _______________________________________________________________________________________ -­‐ all organelles are duplicated before mitosis begins LESSON 7: MITOSIS & CYTOKINESIS THE CELL CYCLE CONTINUED At the end of interphase, the cell continues to grow and make proteins in preparation for mitosis and cytokinesis. MITOSIS •
Mitosis is the shortest stage of the cell cycle •
As the nucleus prepares to divide, replicated DNA from interphase joins to form __________________, joined by a ____________________. •
MITOSIS OCCURS IN 5 STAGES: 1. Early Prophase 2. Late Prophase 3. Metaphase 4. Anaphase 5. Telophase STAGE 1: ______________________ -­‐ replicated DNA coils up into X shaped chromosomes -­‐ nucleolus disappears/nuclear membrane break down -­‐ spindle fibers form from centrioles (organelles that organize the spindle fibers STAGE 2: _______________________ -­‐ Spindle fibers attach to centromeres of chromosomes -­‐ Nuclear membrane has now completely disappeared STAGE 3: _______________________ -­‐tugging action of the spindle fibers pulls the chromosomes to the middle -­‐chromosomes then align on the equator of cell STAGE 4: _______________________ -­‐spindle fibers contract and shorten and pull sister chromatids to opposite poles of cell -­‐Centromere splits -­‐Once the sister chromatids are pulled apart they are individually known as chromosomes STAGE 5: _______________________ -­‐One complete set of chromosomes is now at each pole of the cell -­‐Spindle fibers disappear -­‐Nuclear membrane forms around each separated set of chromosomes TO RECAP…….. THE END OF TELOPHASE •
A nucleolus appears within each nucleus •
So at the end of ________________ there are 2 nuclei in one cell •
The cell is now ready to divide •
This division is called _________________ CYTOKINESIS •
Separates the 2 nuclei into 2 daughter cells •
These daughter cells are identical to the parent cells •
Cell membrane pinches together to divide the cytoplasm and organelles MITOSIS ACTIVITIES •
STEP 1: Genome BC Activity worksheet to summarize what is happening during mitosis •
STEP 2: Draw a schematic of mitosis •
Using the 11x17 provided sheet draw out the phases of mitosis (see page 156-­‐157 in your text) •
For each of the 5 steps of mitosis you must write in point form what is happening at each step •
Draw a schematic picture of what is happening in the cell for each of the 5 steps LESSON 8: CELL CYCLE CHECKPOINTS AND CANCER Recall the Cell Cycle…here is some new terminology •
The first phase of interphase for growth and preparation is also called the G1 Phase •
The second phase of interphase where DNA replication takes place is also called the S phase (synthesis phase) •
The third phase of interphase where continued growth and preparation occurs is also called the G2 Phase •
Mitosis is also known as the M phase •
There is a checkpoint in G1, G2 and M phases to ensure cell division is occurring properly CHECKPOINTS IN THE CELL CYCLE WILL PREVENT DIVISION IF: -­‐ If the cell is short of nutrients -­‐ _________________________________________________ -­‐ If the DNA is damaged CANCER AND THE CELL CYCLE •
If there is a mutation in a gene that produces instructions for a checkpoint protein the cell cycle will be lost •
To summarize: ______________ à _________________ à ________________ à = cancer •
Normal, healthy cells grow in a single layer and stop dividing when they receive messages from neighbouring cells •
Cancer cells don’t do this and they start to grow in multiple layers à ____________ HOW DO TUMORS GROW FROM A MUTATED GENE? •
____________________________________________________________________________________ •
Ex-­‐a cancer cell in your lung will not function like a lung cell •
____________________________________________________________________________________ •
This is also how you get multiple tumors as cancer cells can use the blood vessels to move to new locations and start a new tumor SCIENCE WATCH PAGE 164: STOPPING THE CELL CYCLE CLOCK •
By yourself…read the article “Science Watch” on page 164 •
Brainstorm with a partner…the answers to Q 1-­‐3 •
Ticket out the door…write your thoughts to the answers to Q 1-­‐3 on a slip of paper and hand it in to me before leaving today LESSON 9: ASEXUAL REPRODUCTION OVERVIEW OF ASEXUAL REPRODUCTION •
________________________ •
Asexually produced offspring are called ___________ •
____________________________________________ •
Unicellular organisms (composed of one cell) asexually reproduce quickly and in large numbers TYPES OF ASEXUAL REPRODUCTION •
There are 5 types of asexual reproduction we will be learning about: •
______________ •
Budding •
______________ •
Vegetative Reproduction •
______________ YOUR TURN FIRST… •
Pretend you are a scientist and you need to find out about the 5 types of asexual reproduction •
Use the handout provided and your text book to find out information on the 5 types of asexual reproduction METHOD OF ASEXUAL REPRODUCTION #1 BINARY FISSION •
________________________________________________________ •
A single parent cell replicates its genetic material and divides into 2 equal parts •
Example: Amoeba BINARY FISSION IN BACTERIA •
______________________________________ •
Bacteria have no nucleus and a single chromosome which replicates during binary fission •
If conditions are right, bacteria can reproduce every 20 min àthis is why you can sick very very fast! METHOD OF ASEXUAL REPRODUCTION #2 BUDDING •
____________________________________________________________________________________ •
Unicellular yeast also reproduces by budding •
An outgrowth or bud forms on the parent •
The bud may detach from the parent and become a new individual or remain attached METHOD OF ASEXUAL REPRODUCTION #3 FRAGMENTATION •
______________________________________________________ •
If an organism is injured and loses part of its body, each fragment can develop into a complete clone of its parent •
Example: sea star, flat worm •
Each fragment of the organism ___________________ into a clone of its parent METHOD OF ASEXUAL REPRODUCTION #4 VEGETATIVE REPRODUCTION •
___________________________________________________________________________________ •
Examples of plants that do this type of reproduction: tulips, daffodils, hyacinth, strawberries and potato sprouts •
Disadvantages for the plants: ___________________________________________________________ •
Advantages to humans: _______________________________________________________________ •
(grafted apples trees produce fruit in 2-­‐3years where an apple tree grown from seed takes 5-­‐10 years to bear fruit) METHOD OF ASEXUAL REPRODUCTION #5 SPORE FORMATION •
Spores are made by some bacteria, fungi and puffballs •
____________________________________________________________________________________ •
Spores are light weight and rely on water or wind to transfer them away from their parents •
Many spores have a tough outer covering to protect them from extreme conditions ADVANTAGES OF ASEXUAL REPRODUCTION: A SUMMARY •
A large number of offspring can be produced in a short time •
You only need one parent •
Large numbers of organisms helps them survive when there are predators or when conditions change •
Large colonies also can out compete other organisms for nutrients and water DISADVANTAGES OF ASEXUAL REPRODUCTION: A SUMMARY •
Offspring are genetic clones therefore a mutation could potentially wipe out an entire colony •
Some methods of asexual reproduction produce offspring close together where there is competition for food and space •
Unfavourable conditions can wipe out an entire competition Ex: extreme temperatures LESSON 10: HUMAN ASSISSTED CLONING We’ve talked about plant assisted reproduction…what about human assisted reproduction…also known as CLONING. •
We will discuss 2 types of human assisted cloning: 1. ________________________________ 2. ________________________________ REPRODUCTIVE CLONING •
Also called _______________________ •
Why do it? Produces a genetic duplicate of an existing organism who perhaps has desirable qualities •
The first organism to be cloned is DOLLY! THERAPEUTIC CLONING •
_______________________________________________ •
______________: cells that have the potential to become many different types of cells •
Can use human embryonic stem cells and adult stem cells •
Embryonic stem cells are most desirable for this technique because they can become any one of our 200 types of body cells •
Embryonic stem cells can be used to replace damaged cells in patients with diseases such as diabetes, spinal injuries and Parkinson’s •
Adult stem cells from bone marrow have been used in transplants for 30 years (bone marrow transplants) •
Step 1: __________________________ •
Step 2: remove the nucleus from a donor •
Step 3: ______________________________________________ •
Step 4: embryonic stem cell start to grow •
Step 5: _________________________________________________________ •
Step 6: transplant the cloned cells back into the patient •
SHOULD WE CLONE HUMANS? •
Brainstorm with a partner with whatever knowledge you have of cloning to decide whether you think it is ethically right to clone human beings? •
Record your thoughts on a piece of paper with your reasoning why. •
We will watch a 4 part BBC video on human cloning (36 min) •
At the end you will look at what your pre-­‐thoughts were and see if they have changed based upon the knowledge in the video. •
Please understand that cloning of humans is a VERY CONTROVERSIAL SUBJECT! LESSON 11: SEXUAL REPRODUCTION AND MEIOSIS •
•
Mitosis à •
every cell in your body undergoes mitosis EXCEPT sperm/egg cells •
In mitosis cell division occurs once •
Your body cells all have 46 chromosomes •
Produces identical daughter cells Meiosis à •
ONLY _____________________________________ •
In meiosis cell division occurs twice: once at the end of meiosis I and once at the end of meiosis II •
Your sperm/egg cells (gametes) all have ________________________ •
Produces cells with shuffled genetic information = variation in gamete Q: Why do you think gametes have only 23 chromosomes? SEXUAL REPRODUCTION •
Requires 2 parents •
Produces offspring that are genetically ______________ from each other, from their parents and from every other member of their species…you are unique!...unless you’re an identical twin J •
Genetic _______________ is key •
Sexual reproduction randomly sorts, or shuffles, DNA •
Because offspring receive different combinations of their parents DNA, certain organisms may be better equipped for their environment than others (survival of the fittest) THE ROLE OF GAMETES: DIPLOID VERSUS HAPLOID •
•
_____________________ (2n): all body cells have 2 sets of chromosomes •
The diploid number for humans is _____ (2 x 23 = 46) •
______________ ensures that your body cells maintain a diploid number _____________________ (n): gametes have 1 set of chromosomes •
The haploid number for humans is ____ •
Humans inherit 23 chromosomes from their mom and 23 chromosomes from their dad (for a total of 46) •
Gametes have a haploid number of chromosomes •
Male gametes à _______ •
Female gametes à ______ FERTILIZATION •
An egg cell is ________________ by a sperm cell •
The haploid _______________ information from the egg and the sperm combines resulting in a diploid cell called a zygote •
The zygote gets _______ its chromosomes from mom and half from dad •
The zygote undergoes ________________ and cell division to develop into an embryo •
The embryo continues cell division to grow into an organism MEIOSIS -­‐ DNA replicates only ones in interphase before meiosis begins -­‐ 2 complete cell divisions occur once after Meiosis I and once after Meiosis II _________________ •
In mitosis the chromosomes line up on the equator in metaphase and sister chromatids move to opposite poles of the cell •
In meiosis I differs from mitosis because a pair of matching chromosomes (one from each parent) lines up on the equator •
This pair of matching chromosomes is called homologous chromosomes •
Homologous chromosomes separate and move to opposite poles of the cell •
__________________ •
DNA is NOT replicated again before meiosis II •
Chemical messages trigger cell division to begin •
Meiosis II is like mitosis because the sister chromatids are pulled to the opposite poles •
Each daughter cell inherits one chromatid from each chromosome •
Result is 4 haploid cells •
Each cell has half the number of chromosome (23) HOMOLOGOUS CHROMOSOMES -­‐ ____________________ pairs are the same size and shape and have all the same genes -­‐ Each of the colored bands show the same gene horizontally but one copy is from the mom and one is from the dad, therefore, they are not always the same EVENTS THAT PRODUCE VARIATION: CROSSING OVER •
Occurs between each ___________________ in meiosis I •
Parts of sister chromatids _______________ each and ________________ genetic segments of DNA •
The result is each chromosome picks up _________ genetic information…this makes us unique •
This occurs multiple times •
Result: crossing over creates an infinite number of genetic possibilities for just one gamete and results in _____________________ EVENTS THAT PRODUCE VARIATION: INDEPENDENT ASSORTMENT •
When chromosomes line up at the equator they do this _____________, therefore when they split into daughter cells there are many possibilities of what chromosomes go into the resulting daughter cells GAMETE FORMATION: IT’S DIFFERENT FOR MALES AND FEMALES •
•
Males •
Meiosis I produces ___ daughter cells •
Meiosis II produces ___ daughter cells •
These 4 daughter cells become 4 haploid sperm Females •
In females meiosis I produces an _____ (primary oocyte) and a ____________ •
Meiosis II produces one egg (oocyte) and ___ more polar bodies •
Result: one egg (ovum) and ___ polar bodies that never become eggs LESSON 12: SEXUAL REPRODUCTION •
Recall that asexual reproduction requires only one parent •
Sexual reproduction requires 2 parents that bring _____________ gametes together to form a new organism •
There are 3 stages: ____________, _______________, _________________ MATING •
The process by which gametes are in the same ___________ at the same ____________ •
Certain organisms have mating seasons which increase the chances of survival •
•
Sheep, goats and deer mate in the fall/winter so the offspring will be born in the spring when conditions are less harsh Mammals mate on land and in water depending on the species METHODS OF FERTILIZATION •
There are 2 ways that sperm and egg meet to make a fertilized embryo: ____________ and ____________ fertilization •
Once the egg is fertilized cell division (mitosis) will only occur if the following conditions are met: •
There are enough nutrients •
Warm temperature so proteins and enzymes will function •
Sufficient moisture so the embryo doesn’t dry out •
Protection from predators and environmental factors EXTERNAL FERTILIZATION •
Sperm and egg fertilize _____________ of the bodies of the parents •
Common in animals that live in water ex-­‐salmon, sea urchins •
Males and females both release their gametes into the water by spawning •
In plants, mosses and ferns are use external fertilization •
__________________ •
•
Requires little energy to find a mate •
Large number of offspring produced at one time •
Offspring are spread out and don’t compete with parents for food •
Genetic variation is maintained __________________ •
Millions of gametes released but many will not survive •
Embryo’s are unprotected and preyed upon •
Parents do not care for their offspring therefore few survive to adulthood INTERNAL FERTILIZATION •
Orcas and most land dwelling animals including humans reproduce by internal fertilization •
Sperm cells are deposited ________ the female body where they will swim to meet the egg •
Once a sperm has _______________ the egg there is a chemical reaction that prevents any other sperm from entering the egg •
The growing embryo is grown inside the mother and is protected from predators •
Organisms that lay eggs will watch over their eggs until they hatch to protect them from predators •
•
_________________ •
More offspring survive because of protection against predators •
More offspring survive because of parental care _________________ •
Requires more energy to find a mate •
Complex mating behaviours •
Produces less zygotes than external fertilization EMBRYONIC DEVELOPMENT •
Early _________________ that takes place in the first 2 months after fertilization •
After fertilization, the ____________ begins rapid mitosis to produce lots of cells •
At the end of the first week the zygote divides numerous times to make a ________________ (0.2mm) •
The next stage in development is called a ______________ (1.5mm) •
The cells hollow out to form the _______________ •
This happens at approx 2 week after fertilization •
The blastula organizes the cells into 3 layers and as it develops it becomes a ____________…these layers become very important! •
Outside layer à ____________ à forms the skin & nervous system •
Middle layer à ____________ à forms the kidneys, skeleton, muscles, blood vessels, reproductive organs •
Inner layer à _____________ à forms the lungs, liver and lining of the digestive system •
The center is hollow FETAL DEVELOPMENT •
At the end of gastrulation cells are organized into ectoderm, mesoderm and endoderm •
These cells will undergo ____________________ to specialize into organs and tissues in the human baby for the next 38 weeks (a human pregnancy is 40 weeks) •
Differentiation occurs in 3 trimesters approx 3 months long each FIRST TRIMESTER •
The first ____ weeks make up the first trimester •
All organ systems begin to develop and are they are completely formed by the end of 12 weeks •
Week 4 -­‐ ________ and spinal cord •
Week 8 -­‐ ________ cells form •
The fetus is approx 28 g in mass and 9 cm long •
NOTE: the growing baby is called a FETUS at 8 weeks gestation SECOND TRIMESTER •
Fetus grows rapidly from 12-­‐16 weeks •
Growth slows between 20-­‐24 weeks •
Mom can feel the baby kicking by week 20 •
By the end of the second trimester that fetus weighs 650 g and is 35 cm long THIRD TRIMESTER •
Fetus continues to grow and put on weight •
Significant growth in the ________ •
Week 32 the baby starts accumulating fat under the skin to keep the baby warm after birth •
At the end of the third trimester the fetus weighs approx 3300 g and is 40-­‐50 cm long SUMMARY OF MAIN EVENTS IN FETAL DEVELOPMENT Trimester
Stage
Time from
Fertilization
Length of Embryo
/Fetus
First
-brain and spinal cord form
-digits appear
-ears, kidneys, lungs, liver,
muscles develop
-sex differentiation almost
complete
-4 weeks
-8 weeks
-8 weeks
-12 weeks
-4 mm
-4 cm
-4 cm
-9 cm
Second
-fetal movements felt
-eyelids open
-continued growth
-16-18 weeks
-24 weeks
-20 cm
-35 cm
Third
-rapid weight gain
-accumulation of fat
-26-38 weeks
-40-50 cm
LESSON 13: ASSISTED REPRODUCTIVE TECHNOLOGY OVERVIEW •
_______________: the inability to have a baby •
Some reasons for infertility •
Males that can’t produce enough _________ •
Females that are unable to produce enough ______________ for pregnancy •
•
Females that have __________ fallopian tubes •
Medical treatments such as chemotherapy Assisted reproductive technologies: help couples have a baby by alternative methods •
Artificial insemination •
In vitro fertilization •
Gamete intrafallopian transfer •
Intracytoplasmic sperm injection ARTIFICAL INSEMINATION (AI) •
Technique for _____________ sperm from a male and ______________ it into a female •
The technology was first developed for animals more than 200 years ago •
Today this technology is widely used to breed farm animals IN VITRO FERTILIZATION (IVF) •
One common fertility problem occurs when woman’s fallopian tubes are blocked so the egg and sperm cannot meet •
In IVF eggs are taken out of the mother and the sperm is donated from the fatherà they get combined in a ______________ in a ________ •
2-­‐4 days after fertilization the embryo’s are placed _________ inside the uterus of the _____________ •
More than one embryo is implanted therefore there is a higher chance of multiple births •
Woman undergo extreme hormone treatment to increase the number of eggs produced •
The chance of success is 1 in 3 and the older the mother is the less likely IVF will be successful GAMETE INTRAFALLOPIAN TRANSFER (GIFT) •
Eggs are removed and sperm is donated to produce a mixture of sperm and eggs •
The mixture is ________________ injected into the woman’s fallopian tubes so that fertilization takes place ____________ the mother •
This is different from IVF because fertilization does not take place in the lab but rather in the mother INTRACYTOPLASMIC SPERM INJECTION (ICSI) •
Very _________________ procedure where a single sperm is _____________ into an egg cell •
The resulting zygote is then inserted into the uterus of the mother •
Used when a man has a very low sperm count or if IVF has been unsuccessful •
About 25% of all ICSI procedure result in a baby THE IMPACT OF TECHNOLOGY •
_______________ chance of birth ______________ and rare genetic disorders •
Leftover embryos are __________ and could be used for _________ cell research but this is controversial à who owns these embryos??? •
Artificial insemination can be from a anonymous donor so the child will never know its father •
________________à having another female carry a couple’s pregnancy to term à again its controversial as people can change their minds •
The result: this technology is helpful to a lot of couples but there is much controversy on whether it is the right thing to do THE END OF THE BIOLOGY UNIT!