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Flashcards in Exam 1 Deck (80):
1

Transmission genetics

Describes how traits are padded from 1 generation to the next. It looks at the individual organism and how it inherits it’s gene make up

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Molecular genetics

Chemical nature of gene. Focuses on gene, structure, and function

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Population genetics

Studies the genetic composition of the same species and how the composition changes. It focuses on a group of genes in a population

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What makes a good model organism

Short generation time, adaptability to lab, a manageable number of progeny, and inexpensive to rear

5

What makes up a chromatin?

DNA wrapped around his tones. The Justine’s without linkers is called a nucleosome

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What is a Karyn type?

Looking at a picture and chromosomes me features and size

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What does a meta centric chromosome look like

The centromere is in the middle

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What is a sub centric chromosome

Centromere is a little above middle

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What is a Afrocentric chromosome

There are only tiny amounts of dna above centromere

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What is a telocentric chromosome

Only centromere visible on top part of chromosome

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What happens in interphase?

The chromosomes are replicated and the cell prepares

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What happens during prophase?

The chromosomes condense and the spindle forms

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What happens during metaphase?

The chromosomes line up along the middle metaphase plate

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What happens during anaphase?

The chromosomes separate and go to separate poles. This phase has 2x # of chromosomes

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What happens during cytokinesis?

Cytoplasm divides

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When does crossing over take place?

Prophase 1

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What is different about meiosis?

In meiosis 1, the homologous chromosomes line up next to each other so when the cell divides the daughter cells are haploid

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How many cells does meiosis end up with?

4

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Does meiosis have 2 dna replication stages?

No only 1 before meiosis 1

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What is the subunit of spindle fibers?

Tubular

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What do kinetochore microtubules do?

They shorten at the + end to pull the chromatids to opposite ends towards the - end

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What do polar microtubules do?

The elongate the cell by adding to the + end while motor proteins move to the + end

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What Jeep’s sister chromatids and homologous chromosomes together?

Cohesion

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What breaks down cohesin

Separate

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Why don’t sister chromatids separate during meiosis 1 when homologous chromosomes separate

Shugosin protects it

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How many viable gametes from spermatogenesis?

4

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How many viable daughter cells from oogenesis?

1

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What are gametes called after first meiotic division?

Secondary spermatocytes and oocytes

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What are gametes called after prophase 1?

Primary spermatocytes and oocytes

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Bivalent def

A synapses pair of homologous chromosomes

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Synapsid def

Close pairing of homologous chromosomes

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Disjunction def

Separation of chromosomes

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Chiasma def

Place where crossing over occurs

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What are the 3 essential elements of a chromosomes?

Centromere, origin of replication, and telomeres

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Pan genesis def

Early theory of genetics that genetic info from the body travels to the reproductive organs where it is transferred to gametes

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Preformatism def

A tiny version of the adult human( humunculus) is present in either sperm or egg

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What is blending inheritance?

Theory that sperm and egg have essences that are blended

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What did Mendel do differently?

Worked quantitively, used clear cut traits, true breeding

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Allele def

Alternate form of gene

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Locus

Place occupied by allele on chromosome

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Homozygous

2 of the same alleles

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Heterozygous

2 different alleles

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Dominant

Trait expressed in f 1

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Recessive

Trait not expressed in f 1

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Text cross

Cross with homozygous recessive to see the genotype(if homo or Herero)

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Reciprocal cross

Shows whether trait is sex linked by switching male and female

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Backcross

Crossing f1 with p

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True breeding

Homozygous for trait

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Mendels 1st law

Alleles segregate during gamete formation, 1/2 have 1 allele half have other

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Mendels 2nd law

Different genes assort independently in gamete formation

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Multiplicative rule of probability

2 independent events, probability of happening together, multiply separate events

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Additive rule of probability

2 independent events, you can find probability by adding probability

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What are the 6 extensions of Mendelian genetics?

Pleiotropy, dominance variations, incomplete penetrative, variable expressivity, variations in viability, and gene interactions

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Pleiotropy

One gene affects more than one trait

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Incomplete dominance

Phenotype of heterozygous is intermediate between the phenotype of the two homozygotes

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Codominance

The heterozygous phenotype includes phenotype of both homozygotes

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Incomplete penetrative

Less than 100% of genotype shows correct phenotype

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Variable expressivity

All of genotype show phenotype but there is some variation

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Variations in viability

Some traits cause death of offspring before birth so you don’t see it in genotype

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Gene interaction

Multiple genes effect 1 trait

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Dominant epistasis ratio

12:3:1

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Recessive epistasis ratio

9:3:4

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Duplicate recessive epistasis

9:7

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Duplicate dominant epistasis

15:1

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Duplicate interaction

9:6:1

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Dominant and recessive epistasis

13:3

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Heterogenetic gender

Gender that can produce different types of gametes. Ex: male humans

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Homogametic gender

Produce same genotype in gametes ex: female human

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What are some of the sex determining mechanisms?

Haplodiploidy, which occurs in bees is where the haploid male undergoes mitosis to make a 1n sperm and the diploid female undergoes meiosis is to make 2 1n eggs. The egg that is fertilized is female and the egg that is not is male.
ZZ-ZW: males are ZZ, females are ZW
XX-XY: humans
XX-XO: females XX, males X and then no other chromosome
Environmental sex determinism

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Sequential hermaphroditism

Each individual can be male or female but not at the same time. Ex: limpet, the 1st is female, sequentially males then switches

71

How are drosophila different than humans in sex determinism?

Drosophila are male or female depending on the ratio of sex chromosomes to autosomal chromosomes

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What is evidence for chromosomal theory of inheritance?

T.H Morgan and Calvin bridges

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What is Turner syndrome?

Turner syndrome is a female with only One X chromosome. They are sterile with underdeveloped sex organs and a web of skin

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What is Klinefelter syndrome?

A male with two X chromosomes and one Y who is sterile with underdeveloped sex organs and tall and lanky

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How do you determine the most likely mode of inheritance? Autosomal recessive

Autosomal recessive traits appear equally in males and females and skip generations. They are more likely to appear in progeny if related parents

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Autosomal dominant pedigree

Appear equally in males and females
Unaffected persons do not transmit the trait
Affected persons have at least one affected parent

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X linked recessive pedigree

An affected male does not pass trait to sons but can pass to daughter making heterozygous and unaffected. X-linked recessive appear more frequently in males and a female who carries it can pass to sons who are affected.

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X-linked dominant pedigree

X-linked dominant does not skip generations, affected males pass to all daughters
If affected females are heterozygous, they pass trait to half sons and half daughters

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Y-linked pedigree

All male offspring are affected of a male who had trait

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How do you determine the most likely mode of inheritance?

By looking at the probabilities of the observed outcomes