Genetics Exam 1 - Review

Question 1

Gene

Answer 1

Segment of DNA that contains the information to produce a functional prodcut-protein

Question 2

Trait

Answer 2

Characteristic of an organism

Question 3

Allele

Answer 3

Alternative version of a specific gene (genotype)

Question 4

Genome

Answer 4

Collection of all the genes

Question 5

Proteome

Answer 5

Collection of all the protein in an cell type

Question 6

Homologous Chromosomes / Homologs

Answer 6

Not 100% identical, they are very similar but not identical. One comes from your mom and the other comes from your dad during meiosis I

Question 7

Sister Chromatids

Answer 7

100% identical in mitosis and meiosis II

Question 8

Natural selection

Answer 8

When the environment selects for traits/phenotypes that confer greater reproductive success

Question 9

Morphs

Answer 9

A form of phenotype that varies within a population

Question 10

Genetic Variation

Answer 10

Genetic differences among members of the same species or different species

Based upon changes in the DNA code (nucleotides changes)

Question 11

Mendel’s law of segregation

Answer 11

Separation of homologous chromosomes (anaphase I)

homologs

Question 12

Mendel’s law of independent assortment

Answer 12

Random alignment of different bivalents / homologous chromosomes (metaphase I)

Question 13

Synaptonemal complex

Answer 13

Links together homologous chromosomes in meiosis I (chromosomes come in for a hug)

Question 14

Chiasma

Answer 14

Physical structure that is formed when two chromatids cross over

Question 15

Bivalents

Answer 15

Pair of homologous chromosomes

Question 16

Dosage compensation

Answer 16

Refers to the phenomenon in which levels of expression of many genes on the SEX CHROMOSOMES is similar in both sexes even though males and females have different pairs of sex chromosomes

Since females have XX they have more genetic material than males which are XY

to compensate, one of the X’s in females will be deactivated and turned into a barr body

Question 17

Sex-linked inheritance

Answer 17

When the inheritance is linked to the X chromosomes, sex-linked = x linked

Question 18

Endosymbiosis

Answer 18

Describes a symbiotic relationship in which the symbiote lives inside the host (ex: mitochondria and chloroplasts)

Question 19

Overdominance

Answer 19

Heterozygous Advantage

When the heterozygous genotype conferees better reproductive success over the homologous genotypes

Question 20

Incomplete dominance

Answer 20

This pattern occurs when the heterozygote has a phenotype that is the intermediate between the homozygous dominant and the homozygous recessive

Ex. Red = RR, white = rr, pink = Rr

Question 21

Gene Interaction

Answer 21

The Phenomenon in which the presence of different genes influence the outcome of a single trait

Question 22

Lethal alleles

Answer 22

When one of the alleles is deadly

Question 23

Epistasis

Answer 23

When one gene masks another gene

Ex. flower has a recessive allele like cc and pp and it will mask any of the dominant phenotypes (Ppcc will be white)

Question 24

Pleiotropy

Answer 24

When one gene has multiple effects

Question 25

Incomplete penetrance

Answer 25

When dominant phenotype is not expressed even though an individual carries a dominant allele

Ex. you carry the polydactyly allele (a dominant allele) but you have a normal number of fingers

Question 26

Variable Expressivity

Answer 26

Refers to the spectrum of phenotypic expression. Everyone has the same gene but there is a spectrum

Ex. you have polydactyly and you have an extra finger and your brother has 2 extra fingers and sister has 3 extra fingers

Question 27

Cytoplasmic inheritance

Answer 27

A inheritance of extranuclear DNA

Ex. mitochondria and chloroplasts

Question 28

Heteroplasmy

Answer 28

The condition of a cell that contains variation in a particular type of organelle

Ex. Plants with white and green have a combination of two different type of chloroplasts

Question 29

Gene imprinting

Answer 29

A pattern of inheritance that involves a change in a single gene or chromosome during gamete formation. This is a type of epigenetic. The mode in which this occurs is by methylation

Question 30

Parental leakage

Answer 30

The contribution of mitochondria by the sperm cell to the zygote

Question 31

Materinal effect

Answer 31

When the genotype of the mother directly dtermines the phenotype of the children

Ex. Snail shell coiling
sinestral = left (d)
dextral = right (D)

Mom=dd and Dad=DD
all offpsring will be Dd and will be sinestral (because mom genotype)