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STAR Biology Study Guide
1. DNA  RNA  Protein Synthesis
The physical form of DNA has a Double Helix shape.
DNA is composed of 4-nucleotide bases
Adenine
A-T
* Thymine
Guanine
G-C
Cytosine
RNA is also composed of 4-nucleotide basesAdenine
A-U
* Uracil
Guanine
G-C
Cytosine
Central dogma (idea) of biology: DNA  RNA  Protein
Protein = chain of amino acids
DNA (instructions: code)
 - Transcription DNA  mRNA
mRNAcodons
(3 nucleotide bases = 1 amino acid)
Example:
ATAGCGTCA

UAU/CGC/AGU
- Translation

tRNA (anticodons) carries amino acid to mRNA @ribosome
mRNA (codons) @ ribosome
rRNA ribosome: controls reading frame (3 bases)
Protein = a chain of amino acids
Tyr-Arg-Ser
Variety: The number and sequence (order) of the amino acids.
Note: You will be given a mRNA chart in order to find the amino acids
that match with the mRNA codons (UAU).
* A mutation is a change in an organisms DNA. Mutations are
naturally occurring events.
* Genetic Manipulation  Genetic Engineering. GMO. Transgenic
organisms.
Scientists insert genes (DNA) into organisms. Transformation.
DNA Replication: DNA makes an exact copy of itself before cell
division.
chromatin  chromatids (S phase of cell cycle)
o DNA unwinds and unzips: helicase
o Free nucleotides pair up according to the base pair rule:
A-T G-C
o DNA polyermase
o Semi-conservative replication
2. Genetics
Genetics is the study of heredity.
Alleles are different versions of the same gene on homologous
pairs. For example, all humans have genes that determine eye
color. Each color is a different allele.
Every individual has two alleles for each gene (pair).
One from their mother and one from their father.
Alleles = genes for a trait / eye color:
B = Brown eyes
dominant
b = blue eyes
recessive
Genotype (Gene pair)
Phenotype (Physical Appearance)
BB- Homozygous Dominant
Brown eyes
bb- Homozygous Recessive
Blue eyes
Bb- Heterozygous (hybrid)
Brown eyes
What percent of the offspring will have blue eyes when you cross a
heterozygous individual with a homozygous recessive individual?
Bb (heterozygous) x bb (homozygous recessive)
Draw a punnett square.
B
b
b
b
Possible Gametes:
If parent diploid cell 2n = TtYy
Then gametes (n):
Sex Determination: Male: XY
sperm: either X or Y
Female: XX egg: always X
Sex Linked Traits: X-linked Genes are carried on the X
chromosome.
Female: XX (can be a carrier) male: XY has only one X, disoder
more likely to be in phenotype
3. Evolution: change / time
Natural Selection (Survival of The Fittest) (Darwin):Those best
adapted for their environment will survive and reproduce. Those
least suited for their environment will die faster and leave less
offspring (children): DIFFERENTIAL REPRODUCTION
Natural selection = a major force that drives evolution.
Adaptation- Phenotypic feature or trait that improves an organism’s
likelihood of survival and reproduction. Example- Humans have
opposable thumbs which allow us to grip objects better than other
animals.
Speciation- The formation of a new species. Speciation is a result of
Geographic Isolation and Reproductive Isolation of a certain species.
Speciation: NEW SPECIES EVOLVE
BUT there are PRE-ZYGOTIC & POST ZYGOTIC reproductive
BARRIERS.
Proof of evolutiono Fossil record
Sedimentary rock
Fossil = A piece of organism or imprint left behind.
Fossils show that species have changed over time.
o Vestigial structures
Body structures that have shrunken and are not used anymore.
Example- Tail bone in humans.
o Homologous structures
Structures that share a common ancestry and look/behave
similarly.
Example- Human and whale bone structure.
o Embryology
Comparing development.
o DNA homology (similarities in DNA sequences)
Comparing DNA sequences. Human DNA is 99% the same as
chimpanzee DNA.
o Artificial selection: MAN selects. NOT environmental factors.
Humans select for traits they want . For example- Humans
breed dogs and horses to get traits they desire.
4. Cell Biology
ALL cells have which structures? Draw
Prokaryotic Cells: No nucleus
These cells contain no membrane bound organelles. These
cells are simple and not complex.
Example- Bacteria cells are prokaryotic.
Draw:
Eukaryotic Cells: Nucleus +
membrane bound organelles.
These cells are very complex.
Example- Plant and Animal cells are Eukaryotic.
Cell Organelles:
1. Nucleus: Located near the center of the cell: DNA .
DNA = instructions to make proteins (chain of amino acids)
Transcription
2. Mitochondria: “Power house of the cell”. Cell energy = ATP is
produced: aerobic cellular respiration.
3. Lysosome: molecules and wastes are chemically broken down /
so they can be recycled.
4. Ribosome: proteins are made = site of protein synthesis
translation
5. Chloroplast: Site of photosynthesis in plant cells.
6. Rough and smooth ER: Transports molecules within the cell.
ribosomes
makes proteins
detox & makes carbs and lipids
7. Golgi Apparatus: Modifies molecules to make them functional
(able to work), packages, ships.
8. Cell (plasma) membrane: Controls transports in and out of cell /
homeostasis
Passive transport: H L diffusion, osmosis No cell energy needed
Down the concentration gradient
Active transport L  H uses cell energy ATP to pump
Up the concentration gradient
Semi-permeable = Allows selected molecules to enter and leave the
cell.
Osmosis: Solutions / cell
Isotonic
hypotonic
hypertonic
What is the difference between plant and animal cells?
Plant cells have the following organelles that animal cell don’t have1. Cell wall
2. Chloroplasts (contain chlorophyll which trap sunlight for photosynthesis)
Cell Theory: A cell is the fundamental unit of life. All life is made of
one or more cells.
Viruses: are not cells and cannot make proteins with out a host cell.
CELL Cycle: Cell Division: PMAT & cytokinesis
Types of Cell Division: mitosis and meiosis
Mitosis: Asexual / Identical cells produced = clones. Occurs in all
cells except for reproductive cells such as sperm and eggs.
Growth and repair are by mitosis
2n  2n
Meiosis- Sexual / Variety. Produces four haploid reproductive
cells. Meiosis occurs in the testes of males and ovaries of females.
Reduction Division: 2n  n
Diploid cells 2n: Chromosomes come in Homologous PAIRS. Cells
with the full amount genetic material.= genome.
Example- Human diploid cells 2n = 46 chromosomes.
Haploid cells n: Cells with half the amount of genetic material. One
member of each pair. Example- Human haploid cells n = 23
chromosomes.
5. Physiology: Human Body’s Major Systems:
1. The circulatory system- is the body's transport system. It is made
up of a group of organs that transport blood throughout the body. The
heart pumps the blood and the arteries and veins transport it. The
blood, which no longer contains oxygen and nutrients, then goes
back to the heart through veins.
2. The digestive system- is made up of organs that break down
food to small, soluble molecules (monomers): proteins  amino
acids, vitamins, minerals, carbohydrates  sugars, and fats (lipids).
Nutrients which the body needs for energy, growth, and repair.
Digestion  absorption into the circulatory system  all body
cells.
3. The respiratory system- Gas Exchange by diffusion H  L:
O2 in / CO2 out. Includes nose, and tubes: trachea / bronchi, and
lungs: alveoli = air sacs. Gas Exchange. (blood vessels wrap around
air sacs for exchange)
4. The endocrine system-is made up of a group of glands that
produce the body's long-distance messengers, or hormones.
Hormones are chemical signals that control body functions, such as
metabolism, growth, and sexual development.
5. The immune system- is our body's defense system against
infections and diseases. Cells of the immune system- B cells
(produce antibodies), T cells, and macrophages.
6. The nervous system- is made up of neurons in the brain, the
spinal cord, and nerves. One of the most important systems in your
body, the nervous system is your body's control system. It sends,
receives, and processes nerve impulses throughout the body.
7. The muscular system- is made up of tissues that work with the
skeletal system to control movement of the body. Some muscles—
like the ones in your arms and legs—are voluntary, meaning that you
decide when to move them. Other muscles, like the ones in your
stomach, heart, intestines and other organs, are involuntary.
The body is made up of three types of muscle tissue: skeletal,
smooth and cardiac muscle tissues.
9. The skeletal system is made up of bones, ligaments and
tendons. It shapes the body and protects organs. The skeletal
system works with the muscular system to help the body move.
Marrow, which is soft, fatty tissue that produces red blood cells, many
white blood cells, and other immune system cells, is found inside
bones.
All these systems work together to maintain homoeostasis(balance).
6. Ecology: Ecosystems Interactions: biotic / abiotic
Energy Pyramid: Trophic levels = community
10% Law of Energy Transfer
o Constant Input of energy is required
o Materials Cycling: Geochemical Cycles:
o Carbon
o Nitrogen
o Water
Relationships: Symbiotic:
++
+0
+-
Predator / prey
Social
Limiting factors
Range of Tolerance
Biodiversity
Ecological Succession: change in the community in an area over time.
Continues until a climax community = stable ecosystem
* Primary succession: Rock  soil building -- pioneer organisms (lichen) …
grasses … shrubs.
 Secondary succession: a disaster occurred (fire.) soil present  grasses …
Order of succession in the population of an area starts off with simple organisms
then over time the organisms become more complex.
Photosynthesis: (autotrophs only)
o H2O + CO2  C6H12O6 (food) + O2 (waste / air)
Respiration: ALL cells / ALL the time
o C6H12O6 + O2  36 ATP (energy) + waste: H2O + CO2
o Glycolysis (cytoplasm) Aerobic (mitochondria)
1. Scientific Method: OBSERVATION 1st  Hypothesis  Experiment
(control & variable). In an experiment, the length of study is often an
unavoidable source of experimental error.
2. People with HIV contract infections that are rare in the rest of the
population because people with HIV are unable to fight off these infections
with their weak immune system. (HIV attacks wbc: Helper T cells)
3. Vaccines- promote the production of antibodies by white blood cells.