Bio Spring Study Guide

8/6/2019 Bio Spring Study Guide

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BIO FINAL REVIEW

Genetics

1) Codominance - both alleles of a gene contribute to the phenotype. Erminette chickens have

speckled black and white feathers. The alleles are given subscripts or superscripts.

Incomplete Dominance - the phenotype is a combination of the two alelles, ie a blending of what two

homozygous organisms would look like.

2) Dihybrid crosses predict the alleles for two traits in offspring. Each of the different possible

gametes (up to four) creates a new row or column. Ex:

AaBb allows for AB, Ab, aB, and ab gametes.

AABB can only produce AB gametes.

If both parents' are heterozygous, offspring are found in the ratio

1:2:1:2:4:1:2:1:2 genoytpically and 9:3:3:1 phenotypically.

3) Pedigrees are 'family trees' and show heritage of traits. Generations are listed as roman

numerals (I, II, III, IV) and individuals are named from left to right as numbers (1, 2, 3, 4).

Females are circles and males are squares. Afflicted individuals are shaded in black. Sometimes

carriers will be half shaded (ex. hemophilia) but DON'T have the disease, since it is recessive.

How to Determine: Recessive Traits

-If neither parent has the trait but at least one offspring does.

-Most likely, there will be more people that do not have the trait.

Dominant Traits

-If a parent is homozygous for the trait and passes it to all his offspring.

Remember, people linked via marriage (a horizontal line) in later generations are not part of the

same family as people above them in the tree. Ew incest.

4) A trait can be controlled by multiple alleles if there are more than 2 possible forms of a gene.

The organism still only has two alleles. Codominance and incomplete dominance can still

occur. Ex:

Human blood type is controlled by the codominant alleles A and B, and recessive allele O.

Polygenic traits are controlled my more than one gene and show a wide range of phenotypes.


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The color of pigment in a fly's eye is controlled by three different genes.

5) X-linked traits are controlled by genes on the X chromosome. These traits, like hemophillia

and colorblindness, are sex linked and hereditary. These traits are more common in males, since

they only have one X chromosome. Recessive X-linked traits are less common in females

because they require both parents to have to carry the allele. Females are carriers if they areheterozygous but do not have the trait.

Remember, females pass an X chromosome on regardless of gender.

6) Genes on the same chromosome are said to be linked. These genes create ratios that differ from

standard Mendelian ratios. Crossing over occurs during prohase I.

Linked genes cannot independently assort, limiting the variety of gametes.

The above only results in two gametes (abcde and

ABCDE) instead of 32 if all 5 genes were on different

chromosomes. Since a parent passes down one out of each pair

of chromosomes, genes on the same chromosome stay together.

Crossing over results in a small percent of mixed

phenotypes (here, the last two genes of each chromosome have

crossed over). It's really a very small number. Really.

7) Hereditary Disorders can be passed down from generation to generation. It does not

necessarily have to be sex linked and can be autosomal, ex. Huntington's disease. That's it.

Gene Regulation and Genetic Engineering

*Remember genes are sequences of DNA that

control what proteins are created during translation.

8) Operons: a group of genes that function together (eg, turned on and off by a single operator).

For example, the lactose digesting lac operonin E. coli consists of three genes that are turned

on and off together.

Repressor: blocks transcription of certain gene sequence(s) on the DNA strand. In order to turn the lac

gene on, lactose must be present in the bacterium to bind to the repressor. It then falls off, allowing the

lactose-digesting proteins to be synthesized. If no lactose is present to remove the repressor, the gene is


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not transcribed.

Operator: (The book calls this the O-region a lot) area where repressors bind to regulate transcription

of an operon. It is generally found between the promoter (where RNA Polymerase binds to) and the

operon itself.

9) The TATA box Is a short region of ~30 base pairs that are found right before the sequence to betranscribed (but after the promoter sequence). Meant to help position the RNA polymerase.

10) Hox genes control differentiation of cells and tissues in the embryo. They are similar among a

wide variety of species, from mice to flies to humans. May be proof that organisms once shared

a common ancestor.

11) Genetic engineering aims to make changes in the DNA of a living organism. Transgenic

Organisms are organisms that contain genes from other species. Recombiant DNA is DNA that

comes from multiple sources.

12) Medicine:

Transgenic bacteria grow fast and are used to produce insulin for diabetics, HGH for

short people(I could use some), and clotting factors for hemophillia.

Substances are mass produced cheaply. In the future, may be able to produce chemicals

for curing cancer and materials for synthetic plastic.

Animals with human genes are used to study diseases on the human immune system.

Agriculture:

GM animals increase food supply. Hormones allow animals to grow fast and produce

better meat.

GM plants can produce a natural pesticide for weed killing. Also a possibility to create

antibodies, plastics, and rot-resistant.

13) a. DNA is extracted from a cell using chemicals.

b. DNA is cut using restriction enzymes that only cleaves a specific nucleotide sequence.

The resulting fragments are called restriction fragment length polymorphisms. (RFLP)This also creates sticky ends on the two sides of the fragment.

c. Gel electrophoresis separates the DNA fragments. The negatively charged molecules

move towards the positive end of the gel. The smaller fragments will move farther down.

The fragments are ordered by length and can be compared.

d. Polymerase Chain Reaction- DNA fragment to be copied gets complementary DNA


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attached to each end. These are called primers. DNA is heated to seperate the two

strands and polymerase makes copies of the region between the primers. Each new copy

also serves as a template to make more DNA.

e. To put this DNA in another organism, a plasmid is extracted from a bacterium. The

DNA attaches to the cut plasmid..14) People with similar DNA will have it cut in similar places by restriction enzymes. These

create pieces of similar lengths that are apparent when run through gel electrophoresis

Note how all individuals with an H

allele (Huntington's disease) have DNA

segments cut differently than pure

recessive individuals. RFLP analysis

can help determine a culprit or find

genetic causes of diseases.

15) DNA Fingerprint- the difference in base pairs between every individual allows them to be

identified by their DNA. Is useful in court and criminal justice fields.

16)

Plasmid- circular ring of DNA found in some bacteria. Good for transferring DNA to

new cells.

Vector- agent used to transfer DNA to another cell.

Recombinant- DNA for multiple sources.

Electrophoresis Using gel and electric voltage to order DNA fragments by length.

17) A transgenic organism has DNA that comes from multiple sources.

18) A clone is a genetically identical cell or organism produced from a single cell. First, the

nucleus of an egg cell is removed, since an egg cell is already programmed to develop into a

fetus. The cell is fused with a donor nucleus from another adult cell using electric shock. Once

the cell starts to divide, it is placed in the uterus of a foster mother. The new organism is the

clone from which the donor nucleus came. This process fails a lot.

Evolution, Speciation, and Population Analysis

19) 1785/Hutton the earth slowly changes by the work of geological forces. First to estimate the


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earth to be millions of years old.

1798/Malthus A playwright who wrote the screenplay for Soylent Green. He hates New

York city and likes genre-unsavy detectives. IT'S PEOPLE!Soylent green is people! The human population

would outgrow the resources and supplies available to sustain it. Darwin observed this in

plants and animals, since they produce much more offspring, and only a small fracture surviveto adulthood.

1833/Lyell explained that the same geological forces that shaped Earth in the past are also at

work in the present.

20/21) Lamarck's Evolution Hypothesis/Theory of Need

organisms change because of a need to change and be perfect.

Traits are gained and lost through use and disuse

Acquired characteristics are inheritable.

Darwin's Theory of Evolution

Descent with modification. Evolution occurs via natural selection.

Variation of traits in populations lead for certain members to be better suited for

survival.

Only the fittest can reproduce and pass on theirheritable adaptations while the

unlucky people with unsuitable traits die out.

This heritable adaptation eventually leads to speciation.

22) Evidence of Evolution

1. Common Ancestry

Fossil record shows preserved remains of organisms that are now extinct or similar to

some living organisms,

Geographic distribution has created similar, genetically unrelated species that inhabit

similar environments. While they come from the different ancestors, natural selection

caused them to have common features.

2. Genetic Similarity

Anatomy- homologous structures develop from the same embryonic tissues but look

different when mature. Vestigial structures no longer have a use, but since they don't

hinder an organism, they haven't been eliminated.

Biochemistry- amino acids and proteins or something.

Embryology look similar during early development. Cells develop in the same order


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and produce the tissues growing in similar ways. Ontogeny recapitulates phylogeny

embryos often reflect on evolutionary history.

23) Homologous structures develop from the same embryonic tissues but look different when

mature. Vestigial structures no longer have a use, but since they don't hinder an organism, they

haven't been eliminated.24) Demography- study of populations

25) Geographic Distribution: area inhabited by a population, maybe random, even, or clumped.

Density: individuals per unit area.

Growth Rate: fluctuates, affected by 3 factors, the number of births and deaths, and migration.

Migration is based on environmental factors like (lack of) food or mating.

26) Hardy Weinburg Laws Allele frequencies will be constant if some conditions are met.

27)No migrations, no mutations, no natural selection, no genetic drift, and random mating.

28) (I got a 40 on the quiz so you should listen to me)

Frequency of Alleles p+ q= 1

Frequency of Genotypes in the population - p2 +2pq+ q2 = 1

p frequency of the dominant allele

q frequency of the recessive allele

p2 proportion homozygous dominant

q2 proportion of recessive

2pq proportion of heterozygous

Solve in the order of: q2, q, p, p2, 2pq. For the second generation, turn the population

equation into whole numbers, then solve for p and q, then p2, q2, and 2pq.

29)


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44) Domains supersede kingdoms. There are 3 domains, Eukaryota compassing kingdom Plantae ,

Animalia, Fungi, and

protista, Bacteria for

kingdom Eubactera, and

Archae for Archaebacteria.

45) A cladogram shows the

evolutionary histories of

organisms. The more

branches two organisms

have in common, the more

closely related they are.

46) Dichotomous keys help to identify an organism through its characteristics. Starting from the top,

Follow the instructions and... yeah... work your way

down...

47) Animalia, Chordata, Mammalia, Primates,

Hominidae, Homo, Sapiens.

Dichotomous Keys are generally more legible in the wild.

Microbioligy

48) Characteristics of viruses

Viruses are subcellular particles.

Have only some characteristics of living things.


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Their genetic material (genome) is contained in a protien coat (capsid).

Viruses are obligate parasites of cells, since they cannot reproduce on their own.

They are also species and tissue specific.

Bacteria attacking viruses are called bacteriophages.

49)A virus injects DNA into a cell and one of two cycles starts.

The lytic cycle is virulent. The cell is hijacked and the viral DNA begins to replicate. Protein

coats are created and the new viruses lyse the cell.

The lysogenic cycle is temperate. The viral DNA becomes part of the cell's DNA.The provirus

is replicated and spread to new, intact cells.

50)

Bacteria lack a nuclei and membrane bound organelles. They all have ribosomes and

cell walls.

They can be autotrophic or heterotrophic

reproduce by binary fission (they just sort of split apart).

51) Archaebacteria live in extreme environments (acidic) and temperatures. They have different

lipids in their cell membranes. They may be the ancestors of eukaryotes.

Eubacteria have peptidoglycan in their cell walls. They are more diverse than archaebacteria

and live everywhere.

52) Bacteria are good decomposers. Some live on the roots of legumes and fix nitrogen for other

organisms to use. They help humans produce nutrients and live in your colon. Also digest oil

from oil spills and other toxic substances. They can make lots of enzymes and chemicals.

Plants

91) Cuticles waxy coverings to conserve water.

Enclosed gametes allowed for reproduction without water, gametes didn't dry out.

Mychorrhizae a symbiotic relationship where fungi absorbed minerals for the plant.

Vascular Tissue and vegetative parts = storage, absorbtion, photosynthesis and t ransport.

92) Xylem water transport /

Phloem food transport >_>


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93)

94) Alteration of Generations cycles between sporophyte and gametophyte generations.

Sporophyte generation diploid, plant grows and develops and reproductive structures.

Gametophyte generation haploid and come in the form of seeds or those weird fern bud

things, produce male and female gametes. When a zygote forms, the next sporophyte generation

is created.

95) Gymosperms have 'naked seeds' and produce pollen (male) and seed (female) cones. Seed

cones are generally bigger than their male counterparts.

Angiosperms are flowering plants that reproduce through the use of pistils and st amens.

The stamen contains pollen while the pistil contains the ovule. When an egg is fertilized, and

endosperm is created from the two remaining sperm in the pollen grain. Then, a fruit forms around the

seed. What is it with your fixation for melons.

96)Monocots one cotyledon, when the seed germinates, the shoot has 1 leaf.

Dicot two cotyledons when the seed germinates, the shoot has 2 leaves.

97) Sepals are the outermost circle of floral parts. They enclose the bud and protect the developingflower.

Petals are found just inside the sepals and attract pollinators. Sometimes they are called

sterile leaves because they don't produce gametes.

Stamens consist of a stalk(for support) and an anther that produces pollen. There are

often several stamens in one flower.


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Pistils produce the female gametes. The ovary is located at the base, and inside are ovules that produce

eggs. The narrow tube-like part of the pistil is

called the style, and the stigma is a sticky

portion where pollen lands.

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Bio Spring Study Guide