BIOLOGY
FINAL EXAM
REVIEW
Modern Biology
Chapters:
Protein Synthesis (Chapter 10)
Genetics (Chapter 9)
Human Genetics (Chapter 12)
Evolution (Chapter 15)
Photosynthesis (Chapter 6)
Cellular Respiration (Chapter 7)
Ecology (Chapters 19 – 22)
Protein Synthesis
Review DNA:
• Carries genetic information
for the cell
• Double Helix structure
• Made of repeating nucleotides:
– Sugar (deoxyribose)
– Phosphate molecule
– One of four of the nitrogen bases
A, T, G, C
DNA Replication:
When a DNA molecule replicates, it separates at one
end to form a replication fork. Each strand serves as
a template for synthesis of a new strand.
Protein Synthesis
RNA:
• Carries genetic information
To the site of protein synthesis
Single Helix structure
• Made of repeating nucleotides:
– Sugar (ribose)
– Phosphate molecule
– One of four of the nitrogen bases
A, U, G, C
- Three types: mRNA- messenger; tRNA-transfer; rRNA - ribosmal
Protein Synthesis
The synthesis of proteins takes two steps:
transcription and translation.
Transcription: (happens in the nucleus!)
-
DNA molecule unwinds exposing the portion of DNA
that codes for the protein
- Enzyme, RNA polymerase helps line up nucleotides to
create a complementary strand of mRNA. The new
strand of mRNA is made according to the rules of base
pairing: T – A ; C – G BUT…
Protein Synthesis
Transcription:
BUT… in RNA Adenine (A) pairs with Uracil (U)
What is the mRNA complement to the DNA sequence TTGCAC?
Did you get AACGUG? You are right!
~ Don’t forget that RNA uses the base uracil
in place of thymine ~
Protein Synthesis
Transcription:
Protein Synthesis
Translation: (happens in the
cytosol)
- the new mRNA strand leaves the
nucleus
- mRNA is sent to the cytoplasm,
where it bonds with ribosomes, the
sites of protein synthesis. Ribosome
“Reads” the mRNA one codon at a
time.
- A codon = 3 bases (i.e. AUG )
Protein Synthesis
Translation: (happens in the cytosol)
- tRNA molecules, each associated with specific
amino acids, bind to the ribosome in a sequence
defined by the mRNA codon.
- At its head, tRNA has three nucleotides that
make up an anticodon.
- An anticodon pairs complementary nitrogenous
bases with mRNA.
Protein Synthesis
Protein Synthesis
Translation: (happens in the cytosol)
For example, the codon AUC, will pair with tRNA’s anticodon
sequence UAG.
- The ribosome continues to slide down the mRNA, growing
the polypeptide chain
- Peptide bonds are formed between the amino acids
Protein Synthesis
Translation: (happens in the cytosol)
- The process continues until one of the three
stop codons is reached
- At that point, the protein chain connected to
the tRNA is released. Translation is complete.
Protein Synthesis (Gene Expression )
The process of gene expression/protein synthesis
follows a specific order:
1.
2.
3.
4.
5.
mRNA transcribe the DNA message
mRNA leaves the nucleus
mRNA attach3es to the ribosome
tRNA translates the mRNA codon
amino acids are bonded together (PROTEIN)
MENDELIAN GENETICS
Gregor Mendel
Until the 19th century, scientists
believed that traits from the parents
would blend in the offspring.
For example: a tall father and short
mother results in a child of medium
height, so eventually all members of a
species would look the same.
But in the 1850s, Gregor Mendel, an
Austrian Monk crossed different
strains of garden peas and analyzed
the results. His works laid the
foundation for principals of heredity.
MENDELIAN GENETICS
MENDELIAN GENETICS
From these results, Mendel came up with
three postulates or laws:
1. The Law of Dominant/Recessiveness:
Alternative forms of a trait are controlled by different alleles of
the gene responsible for that trait.
2. The Law of Segregation:
When gametes (haploid reproductive cells) form in diploid
individuals, the two alternative alleles for a gene segregate or
separate from each other. One goes in one gamete, the other in
another…
3. The Law of Independent Assortment:
Every gamete has an equal chance of receiving either member of
an allele pair. Dominant or recessive traits don’t always get
inherited together.
MENDELIAN GENETICS
Some Important Genetics Vocabulary:
• Genetics is the study of the heredity of organisms.
• A gene is a segment of DNA and is the basic unit of
heredity.
• An allele is one of two or more alternative forms of a
gene.
• A recessive gene is one that is phenotypically expressed
in the homozygous (must have both recessive alleles - i.e. bb)
state but is masked in the presence of a dominant gene.
• A dominant gene is one that is expressed phenotypically in
heterozygous (Bb) or homozygous (BB) individual; one that is
shown or present
• Phenotype- physical appearance of an organism – based on
genotype
MENDELIAN GENETICS
Some Important Genetics Vocabulary:
• Heterozygous - a genotype in which the organism carries
different/unlike alleles for a single trait (i.e. Bb, Tt, Ee) –
Sometimes referred to as a hybrid or carrier.
• Homozygous - a genotype in which the organism carries
the same alleles for a single trait (i.e. bb, tt, ee, BB)
MENDELIAN GENETICS
Some Important Genetics Vocabulary:
Incomplete dominance: Sometimes heterozygous
genotypes result in phenotypes that do not precisely
resemble one parent.
• Phenotype is intermediate or “blending” between the
two parental phenotypes (incomplete dominance).
MENDELIAN GENETICS
Some Important Genetics Vocabulary:
• Codominance: Sometimes heterozygous genotypes
result in phenotypes in which both parental phenotypes
can be identified or expressed in the offspring.
GENETICS
Sex chromosomes: chromosomes that dictate the sex of
certain organisms (the remaining chromosomes are called
autosomes).
In humans, there are two sex chromosomes, X and Y.
Males possess one each of X and Y chromosomes.
Females possess two X chromosomes.
Sex-linked inheritance: In humans, a male expresses all
traits unique to the X chromosome he inherits from his mother.
Males are afflicted with X-linked disorders because there is no
counterpart on the Y chromosome to express the functional
allele..
GENETICS
Karyotype: Simply a picture of a person's chromosomes.
You can obtain genetic
information about the
individual:
• Boy or Girl?
• Number and appearance
of chromosomes.
Based on this karyotype,
this individual is a BOY.
REMEMBER: BOY= XY
GIRL = XX
GENETICS
Pedigrees: A pedigree is a diagram that shows the occurrence and
phenotypes of a particular gene and its ancestors from one generation
to the next. Commonly used to trace inheritance of x-linked traits,
such as hemophilia, through generations.
MUTATIONS
A Mutation is a sudden change in the genetic material
of an organism.
**Sometimes harmful to the organism…
~ A dark furry rabbit in the tundra… ~
**Sometimes beneficial when it gives an organism an
advantage to survive and reproduce
For example: ducks webbed feet – the advantage - They
can paddle quicker and more effectively through the
water.
MUTATIONS
TYPES:
Point mutations:
Mutations that affect
single genes through a
base-pair substitution,
deletion, or insertion.
• Point mutations may
have no effect, may
improve or damage the
protein.
MUTATIONS
Chromosomal mutations: Mutations
that affect an entire organism.
• Nondisjunction: An error in
chromosomal distribution during
meiosis, which results in gametes
with an abnormal chromosome
count.
• Polyploidy: A mutation in which
gametes contain more than two full
sets of chromosomes.
MUTATIONS
Mutations can also occur on individual chromosomes. These
include:
• Deletion: A chromosomal fragment gets detached during cell division;
• Duplication: That same fragment joins its homologous chromosome;
• Inversion: That fragment gets reinserted backward; or
• Translocation: That fragment gets attached to a non homologous
chromosome.
The effects of chromosomal mutation are often fatal or can result in
genetic disease but in rare cases may improve an organism’s fitness.
DNA TECHNOLOGY
DNA technology uses Deoxyribonucleic acid (DNA),
to unlock some of the mysteries behind human
behavior, disease, evolution, and aging.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Some DNA-based technologies include:
 Cloning
 PCR
 Recombinant DNA technology
 DNA fingerprinting
 Gene therapy
 DNA microarray technology
 DNA profiling
DNA TECHNOLOGY
For example:
 Cloning - Clones are organisms that are exact genetic
copies. Every single bit of their DNA is identical.
Clones can happen naturally—identical twins are just
one of many examples. Or they can be made in the lab.
DNA TECHNOLOGY
 When scientists clone a gene,
they isolate and make exact
copies of just one of an
organism's genes. Cloning a
gene usually involves copying
the DNA sequence of that
gene into a smaller, more
easily manipulated piece of
DNA, such as a plasmid. This
process, called recombinant
gene technology, makes it
easier to study the function of
the individual gene in the
laboratory.
DNA TECHNOLOGY
For example:
 Recombinant Gene Technology: recombinant DNA
technology is the joining together of DNA molecules from
two different species that are inserted into a host organism
to produce new genetic combinations.
 This is of great value to science, medicine, agriculture, and industry.
EVOLUTION
Evolution is the process by which
species change gradually over
time.
Evolution has led to the
diversification of all living
organisms from a common
ancestor, which is described by
Charles Darwin as "endless forms
most beautiful and most
wonderful“.
EVOLUTION
Jean-Baptiste Lamarck (1744 to
1829) was a French naturalist who is
now infamous for the “giraffes
stretched their necks to reach for
food and therefore gave birth to
offspring with long necks” example of
evolution.
Lamark’s Theory of Inheritance of
Acquired Characteristics, was
eventually disproved
EVOLUTION
Charles Darwin, often referred to as “The Father of
Modern Evolutionary Thought” , traveled for five years
aboard the ship, the H.M.S. Beagle. He studied fossils
that formed in different times. Older and newer rock
layers held fossils that were similar but changed over
time.
EVOLUTION
He also studied plants and animals of the world,
especially those that inhabited the Galapagos Islands.
He formed hypotheses about how and why populations
change. Lots of evidence supports his ideas, so they
are now called Scientific theories.
EVOLUTION
A Scientific theory is not just a guess.
Scientific theories are well-substantiated
explanations of some aspect of the natural world that
is acquired through the scientific method and
repeatedly tested and confirmed through observation
and experimentation.
EVOLUTION
Darwin’s ideas about evolution and natural selection can be
summed up in two theories:
(1) DESCENT WITH MODIFICATION
(2) MODIFICATION BY
NATURAL SELECTION
EVOLUTION
The theory of descent with modification says that
newer species are related to and descended from
earlier species.
EVOLUTION
The theory of Natutral Selection explains that
organisms that are best suited to their environment
are more likely to survive and reproduce.
EVOLUTION
Therefore, individuals with certain traits
more successfully survive and reproduce,
passing those traits to the next generation.
EVOLUTION
Artificial selection:
Humans intentionally breed animals to enhance
specific traits.
Evidence of EVOLUTION
 Fossil Evidence
 Homologous and Analogous
Structures
 Embryology
 Similarities in DNA/Proteins
Evidence of EVOLUTION
 Fossil Evidence:
 The fossil record contains
many well-documented
examples of the evolution
from one species into
another, as well as the origin
of new physical features.
 Evidence from the fossil
record is unique, because it
provides a time perspective
for understanding the
evolution of life on Earth.
Evidence of Evolution
Homologous Structures
– Similar features that originated in a
shared ancestor.
– Different function but structurally
similar (internally).
• Example: penguin wing, alligator leg, bat
wing, human arm---internal structure is
similar, look different, different functions.
Result from: common
ancestry - show they
are related.
Analogous Structures
• Identical functions, different
structure (internally).
– Example: butterfly wings and bird
wings…fly eye and human eye.
Results from: Similar
environments (natural
selection) – does not show
the species are related.
Embryo Development
– Similarities in early stages of embryonic
development (conception to birth) among a
variety of different species.
– Suggest a common ancestor.
Similarities in DNA
– The more closely related two organisms
are, the more similar the DNA sequences.
Energy for Life Processes
• All organisms need energy to survive
•
•
•
•
– Primary source of energy is the sun.
Energy from the sun is in the form of light
energy.
Energy in food is in the form of chemical
energy.
Energy is the ability to do work…
Work for a cell includes growth & repair,
active transport across cell membranes,
reproduction, synthesis of cellular products,
etc.
Energy for Life Processes
How do organisms get this energy from the
sun?
–PHOTOSYNTHESIS-process used by plants
to convert energy from the sun to food
(glucose).
–Cellular RESPIRATION-process that
releases energy in food (glucose) to make
energy (ATP).
Energy for Life Processes
Autotrophic – “self-feeding”
• Autotrophs or producers convert sunlight,
CO2, and H2O into glucose (their food).
– This process is called “PHOTOSYNTHESIS”
• Plants, algae, and blue-green bacteria, some
prokaryotes, are producers or autotrophs .
Autotrophs
Algae & some bacteria
Plants
Energy for Life Processes
• Producers make food for themselves and for
heterotrophs or consumers that cannot make
food for themselves
Heterotrophic – “other-feeding”
• Animals (including humans) represent
heterotrophic organisms.
• Since they cannot make their own food,
humans and other heterotrophs must get
their complex organic compounds (“energy”)
by eating plants or other organisms.
Animals and Fungi are heterotrophs!!
Photosynthesis & Respiration
Once you eat
something, the food gets
broken down into ‘nutrients’,
or smaller molecules the
cells can use.
The bonds that hold these
molecules together contain
energy.
Cells “absorb” broken food
pieces (macromolecules such
as protein, nucleic acid,
carbohydrates, lipids). In the
form of monomers ( building
blocks, such as amino acids,
glucose & fructose, nucleotides
and some smaller pieces of
lipids.).
Photosynthesis & Respiration
• Cellular respiration is the process that
turns food into ATP, a form of energy
that our cells can use.
Photosynthesis & Respiration
• Only autotrophs are capable of photosynthesis
• Both autotrophs & heterotrophs perform
cellular respiration to release energy for
cellular processess.
Biochemical Pathways
• In photosynthesis, CO2(carbon dioxide) and
H2O (water) are combined to form C6H12O6
(glucose) & O2 (oxygen)
6CO2+ 6H2O + Sun’s energy --> 6O2 + C6H12O6
Biochemical Pathways
• In cellular respiration, O2 (oxygen) is used to burn
C6H12O6 (glucose) & release CO2 (carbon dioxide) ,
H2O (water) and energy.
• Usable energy produced in cellular respiration is
stored in the chemical bonds of the molecule
adenosine triphosphate or ATP
ATP = Adenosine TriPhosphate
The energy is harnessed in the phosphate bonds
of an ATP molecule
Photosynthesis & Respiration
Photosynthesis
Cellular Respiration
PHOTOSYNTHESIS
A series of chemical reactions (light & dark
reactions and the Calvin Cycle) where autotrophs
capture light energy to make food (glucose).
Chemical Formula:
6CO2 + 6H2O + sunlight
•Carbon Dioxide water sunlight
C6H12O6 + 6O2
glucose and oxygen
Leaves: Photosynthetic Factories
• Photosynthesis requires
the green pigment
chlorophyll.
• The chemical reactions
of photosynthesis occur
within the chlorophyllcontaining organelles
called chloroplasts.
• These are found inside
cells in plant leaves and
stems.
Light Absorption in Chloroplasts
Chloroplasts - membrane bound
organelles found in plant and algae cells
that absorb light during photosynthesis
They contain:
1. the light absorbing pigments
2. enzymes for photosynthesis
Light Absorption in Chloroplasts
• Photosynthetic cells may have thousands of
chloroplasts
• Chloroplasts are double membrane organelles
with the an inner membrane folded into discshaped sacs called thylakoids
Light Absorption in Chloroplasts
• Thylakoids, containing chlorophyll and other
accessory pigments, are in stacks called granum
(grana, plural)
• Grana are connected to each other & surrounded by a
gel-like material called stroma
• Light-capturing pigments are found in the grana.
Light Absorption in Chloroplasts
Light Absorption in Chloroplasts
How do chloroplasts absorb light??
LIGHT:
Light travels as waves & packets called photons
Wavelength of light is the distance between 2
consecutive peaks or troughs
Light Absorption in Chloroplasts
Sunlight or white light is made of different
wavelengths or colors carrying different
amounts of energy.
A prism separates white light into 7 colors
(red, orange, yellow, green, blue, indigo, & violet)
ROY G BIV
These colors are called the visible spectrum
Light Absorption in Chloroplasts
The visible spectrum:
Each color in a rainbow corresponds to a different
wavelength of electromagnetic spectrum.
Light Absorption in Chloroplasts
When light strikes an object, it is
absorbed, transmitted, or reflected
When all colors are absorbed, the object
appears black
When all colors are reflected, the object
appears white
If only one color is reflected (green), the
object appears that color (e.g. Chlorophyll)
Light Absorption and Pigments
Thylakoids contain a variety of pigments –
molecules that absorbs light - (green, red,
orange, yellow...)
Chlorophyll is the
most common
pigment in plants
& photosynthetic algae
Chlorophyll absorbs
only red, blue, & violet light. Which color does
it reflect?
Light Absorption and Pigments
Accessory pigments trap wavelengths of light that can not be
absorbed by chlorophyll - help capture more light energy
•Carotenoids – reflect orange, yellow, and brown and absorbs
green and blue
•Phycobilins – reflect violet & blue and absorb orange, brown
and green
Overview of Photosynthesis
Photosynthesis is not a simple one step
reaction but a biochemical pathway
involving many steps.
This complex reaction can be broken down
into two reactions:
1. light dependent (Photosystem I & II,
Electron Transport Chain)
2. light independent or dark reactions
(The Calvin Cycle)
Overview of Photosynthesis
Leaves: Photosynthetic Factories
Sunlight
Carbon
Dioxide
CO2
Water
H2O
Oxygen
O2
REMEMBER:
This all-important photosynthetic
reaction can be summarized by the
following chemical equation:
6CO2 + 6H2O + energy (sun)
C6H12O6 + 6O2
• Some scientists consider this process
of photosynthesis the single most
important chemical reaction that
occurs on Earth.
• Why?
Science Fact
• Some scientists have a theory
about the first cells that
appeared on earth about 3.5
billion years ago.
• Early cells had to survive in a
harsh environment. ..
• Why do you think
photosynthesis might have helped
different life forms to appear on
Earth?
THINK OXYGEN!!!
CELLULAR RESPIRATION
• In most organisms, two things
are needed for cells to get
energy: food and oxygen.
• The process by which cells
release energy from food is
called cellular respiration.
• Cellular respiration is carried
out by every cell in both plants
and animals and is essential for
life.
After you eat an apple, your cells are ready to
use that stored chemical energy, but how does
this happen?
The release of energy occurs in a series of
enzyme-controlled small steps:
• The energy stored in glucose is converted
into a usable form, the energy source of all
cells, adenosine triphosphate, or ATP.
• Cells use the energy from
to perform
many functions, such as obtaining materials
and eliminating wastes.
• Cellular respiration is basically the
opposite of the process of
photosynthesis.
• Instead of being produced in the cells,
the energy-rich glucose molecules are
taken apart to release their stored
energy.
• Cellular respiration can be summarized
by the following chemical equation:
C6H12O6 + O2
ATP (energy) + H2O +CO2
Sugar + Oxygen
ATP (energy) + Water + Carbon
dioxide
How do you get energy from ATP?
ATP --> ADP + P + Energy
ATP
P
P
P
ADP
P
P
P
Bond is Broken
Fully
charged
battery
Partially
charged
battery
+
Energy
The “Mighty” Mitochondria
Science Fact
An active cell requires about two million
molecules of ATP per second to perform its
life functions.
Cellular respiration is like burning fossil
fuels – they both break down organic
compounds to release energy and CO2
Science Fact
A steady supply of ATP is so critical for life
that a poison which attacks any of the
proteins used in ATP production kills the
organism in minutes. Certain cyanide
compounds, for example, are poisonous
because they bind to certain atoms which
block the system in the mitochondria where
ATP manufacturing occurs.
PHOTOSYNTHESIS
CELLULAR RESPIRATION
ECOLOGY
What is ECOLOGY??
Ecology can best be described as the
study of living organisms and their
environment as well as how they interact
with their environment.
ECOLOGY
Symbiosis: A relationship in which two kinds of organisms
consistently live together.
•
4 TYPES:
– Predator-prey interactions: Both plants and animals develop
special defenses when they interact competitively with
other organisms.
– Commensalism: A relationship in which one individual is
closely associated with another and benefits without doing
harm to the host.
ECOLOGY
Symbiosis: A relationship in which two kinds of organisms
- Mutualism: A relationship that benefits both organisms
involved.
– Parasitism: A type of predation in which one organism lives
in or on a host and benefits while harming the host.
ECOLOGY AND THE BIOSPHERE
Ecosystems and Biomes
Population: An interbreeding
group of the same species.
1. Every species has a niche
defined by its lifestyle factors
(e.g., behavior, habitat,
predation).
2. Overlap of niches results in
competition until competitors
are eliminated or displaced into
a different niche.
ECOLOGY AND THE BIOSPHERE
Ecosystem:
All the biotic and abiotic factors in an area.
All the living things in an
ecosystem – birds, ants, frogs,
grasses, cactus, worms, lions, etc.
All the non-living things in an
ecosystem – water, sunlight,
temperature, shelter, oxygen
or lack of oxygen, rainfall,
etc.
ECOLOGY AND THE BIOSPHERE
Biome: A large region with distinct plant and
animal life.
ECOLOGY AND THE BIOSPHERE
Energy Flow through an Ecosystem:
Energy in an ecosystem flows among organisms of
different trophic levels.
ECOLOGY AND THE BIOSPHERE
Energy Flow through
an Ecosystem:
Food Webs:
Energy passes from one
animal to another as they
eat plants or one another.
This flow of energy from
one living thing to another
is called a “food web”
Food Chains:
A food chain is a simplified
version of a food web.
ECOLOGY AND THE BIOSPHERE
A “trophic level” is simply a feeding level, as often
represented in a food chain, food web, or an
ecological pyramid.
ECOLOGY AND THE BIOSPHERE
Primary producers comprise the
bottom trophic level
Followed by primary consumers
(herbivores)
then secondary consumers
(carnivores feeding on herbivores),
and so on.
The pyramid does not take into
account decomposers and
detritivores (organisms that feed on
dead organic matter such as
bacteria and fungi), which make up
their own, highly important trophic
pathways.
ECOLOGY AND THE BIOSPHERE
Only 10% of a trophic level’s energy flows to the next; the
rest is lost to respiration, heat, and so on.
ECOLOGY AND THE BIOSPHERE
Cycles in the Environment
Water cycle: Solar energy causes water to
evaporate from oceans into atmosphere. Plants
transpire, also sending water into atmosphere as
vapor. Water vapor condenses into clouds and
precipitates into rain. Rain falls back to Earth,
collects on land as runoff or groundwater, and runs
back into oceans.
ECOLOGY AND THE BIOSPHERE
Carbon cycle: Plants incorporate airborne CO2 into
organic compounds (Photosynthesis!!).
Primary consumers eat plants. When organisms die,
their carbon is locked into fossil fuels or
decomposed by microbes.
Burning of fossil fuels, decomposition of
organisms, and cellular respiration all release CO2
back into the air.
ECOLOGY AND THE BIOSPHERE
Nitrogen cycle:
Nitrogen-fixing bacteria convert atmospheric N2 gas into
ammonium (NH4+).
Nitrifying bacteria convert ammonium into nitrites (NO2–)
and nitrates (NO3–), which are taken in by plants, which
are then eaten by animals.
After plant or animal death, decomposers (bacteria, fungi)
convert nitrogen back to ammonium (NH4+). Denitrifying
bacteria process nitrogenous compounds back into
atmospheric N2 gas.