Genetics

Question 1

Diploid vs haploid organisms

Answer 1

Diploid: two copies of genome per cell
Haploid: one copy of genome per cell

Question 2

In sequel reproduction, the diploid is produced by

Answer 2

The haploid of the mother and the haploid of the father fusing

Question 3

Gene

Answer 3

length of DNA coding for a particular gene product

Question 4

Locus

Answer 4

pinpointing a genes location on a chromosome

Question 5

Human genome has how many chromosomes?

Answer 5

24 chromosome pairs

22 autosomes pairs and 2 allosomes pairs (sex chromosomes)

One from mom, one from dad

Question 6

Homologous chromosomes

Answer 6

Two nonidentical copies of a chromosome

Question 7

Alleles

Answer 7

Different versions of a gene that may carry out the genes function differently

Question 8

Genotype

Answer 8

DNA sequence of the alleles a person carries

Question 9

Heterozygote vs homozygote

Answer 9

Hetero: two different alleles at a given locus

Homo: two identical alleles at a given locus

Question 10

Phenotype

Answer 10

Physical expression of the genotype

Question 11

Dominant vs recessive

Answer 11

Dominant: expressed allele in heterozygote

Recessive: non-expressed allele in heterozygote

Question 12

Can a haploid organism have recessive alleles?

Answer 12

No because there is only one copy of the genome

Question 13

Mitosis produces:

Meiosis produces:

Answer 13

Mitosis prod two identical daughter cells from a parent cell

Meiosis prod one haploid sex cell from a diploid cell

Question 14

Spermatogonia and oogonia

Answer 14

Only cells to undergo meiosis

Question 15

Primary differences between meiosis and mitosis (2)

Answer 15

1. Mitosis has one cell division to make two daughter cells and meiosis has two cell divisions to make four haploid gametes (meiosis 1 and meiosis 2)
2. Recombination between homologous chromosomes occurs in meiosis

Question 16

Steps of Meiosis

1. S-phase: ______
2. Prophase I: chromosomes condense and ______ breaks down, _____ form
3. DNA is cut at the same location on homologous chromosomes, ______ between the pair and chromosomes are _____
4. Metaphase I: _____ align along _____ plate
   5: Anaphase I: homologous chromosomes ____ and _____ remain together
   6: Telophase I: __________ (cells are now considered to be: ______ because they have one set of chromosomes but are still replicated sister chromatids)
5. _________ begins with the ____ process as Meiosis I except that:
6. Anaphase II separates ___________, not tetrads
7. Telophase II produces ________ from the single diploid parent cell

Answer 16

1. S-phase: DNA replication
2. Prophase I: chromosomes condense and nuclear envelope breaks down, tetrads form
3. DNA is cut at the same location on homologous chromosomes, genes are swapped between the pair and chromosomes are realigned
4. Metaphase I: tetrads align along metaphase plate
   5: Anaphase I: homologous chromes separate and sister chromatids remain together
   6: Telophase I: divides into two cells (cells are now considered to be: haploid because they have one set of chromosomes but are still replicated sister chromatids)
5. Meiosis II begins with the same process as meiosis I except that:
6. Anaphase II separates sister chromatids, not tetrads
7. Telophase II produces 4 haploid cells with a single chromosome that is not replicated from the single diploid parent cell

Question 17

Prophase I in meiosis:

What are tetrads?

Answer 17

Chromosomes condense and nuclear envelope breaks down, homologous chromosomes align with each other in synapsis with the two copies of each gene on two different chromosomes brought closely together (tetrad)

Question 18

Metaphase I in meiosis vs mitosis

Answer 18

Meiosis tetrads align at the metaphase plate

Mitosis sister chromatids align at the metaphase plate

Question 19

Nondisjunction

Answer 19

Failure of the sister chromatids or homologous chromosomes to seperate during meiosis

Question 20

If two homologous chromosomes fail to separate how many copies of the chromosomes will the resulting gametes have?

Answer 20

I: One will have four and the other will have none

2: Two will have two and two will have none

Question 21

Trisomy and monosomy

Answer 21

When a gamete from non-disjunction fuses with.a normal gamete to create a zygote with either three copies of a chromosome (trisomy) or one copy (monosomy)

Question 22

Mendel’s law of segregation

Answer 22

Two alleles of an individual are separated and passed on to the next generation singly

Question 23

Mendel’s law of independent assortment

Answer 23

Alleles of one gene will separate into gametes independently of alleles for another gene

If G is green an g is yellow and W is wrinkly and w and smooth then G and W will be inherited independently of one another

Question 24

Cross

Answer 24

Tool to discern genotypes by looking at the phenotypes of progeny from a cross

Question 25

Pure-breeding strain

Answer 25

mating yellow plants with yellow plants produces yellow plants

Question 26

Testcross

Answer 26

One individual is crossed with another that has a homozygous recessive genotype Allows the alleles from one parent to be displayed phenotypically when the other parent is homozygous recessive

Question 27

Progeny of a test cross is called the

Answer 27

F1 generation

Question 28

Probability rules: Rule of multiplication Rule of addition

Answer 28

M: probability of BOTH event A and event B happening is the product of both their probabilities A: probability of EITHER event A or event B is the sum of their probabilities

Question 29

Incomplete dominance

Answer 29

Specific gene does not have one dominant gene but multiple (R for red and W for white for plant color: what would RW express? Pink)

Question 30

Codominance

Answer 30

Two alleles are expressed but are not blended For example blood type: IA and IB would be AB rather than a new blended product

Question 31

Pleiotropism

Answer 31

Expression alerts many different, seemingly unrelated aspects of the total phenotype For ex: a mutation of one gene may affect the heart, bone and inner ears

Question 32

Polygenism

Answer 32

Complex traits that are influenced by many different genes

Question 33

Penetrance

Answer 33

Likelihood of a person with a given genotype to express that phenotype (spectrum of options) -Alleles, mutations, also effected

Question 34

Epitasis

Answer 34

Expression of alleles for one gene is dependent on a different gene (Can't express curly hair gene if other gene says bald)

Question 35

Male or female gamete determines sex of embryo?

Answer 35

Father because he either donates X or Y in meiosis

Question 36

Sex-linked traits

Answer 36

Traits that are determined by genes on the X or Y chromosome because of their unique patterns of expression and inheritance

Question 37

Linkage

Answer 37

Genes on the same chromosome may not display independent assortment

Question 38

Genes close to one another on the chromosome will be inherited

Answer 38

Not independently

Question 39

If the color and height gene display linkage is it possible to predict the possible gametes of TTgg individual? A TtGg individual?

Answer 39

TTgg will just be Tg despite location TtGg cannot be predicted because on each allele could be TG, tg, tG, or Tg

Question 40

Exception to linkage:

Answer 40

Meiotic recombination between homologous chromosomes can separate alleles located on the same chromosome

Question 41

A cross involving genes on the same chromosome result will

Answer 41

Intermediate between linkage and independent assortment

Question 42

Farther apart two genes are, ____ likely to undergo recombination

Answer 42

More

Question 43

If genes are located far enough apart they will display

Answer 43

NO linkage because recombination will be so great and will assort independently

Question 44

Frequency of recombination

Answer 44

(#recombination) / (#offspring)

Question 45

Progeny

Answer 45

Offspring

Question 46

Autosomal Recessive

Answer 46

2 copies of the gene are required to display the trait No sex basis Can skip generation

Question 47

Autosomal Dominant

Answer 47

Single copy of the allele required for trait to be displayed Not sex linked Affected parent passes to all (AA) or 50% (Aa) of children

Question 48

Mitochondrial traits

Answer 48

Inherited from mother because she passes on organelles (inc. mitochondria which has a genome) All of affected females offspring has the trait Individual cannot inherit mitochondrial traits from their father A

Question 49

Sex-linked traits

Answer 49

Traits located on the X or Y chromosome

Question 50

Can a father pass a Y linked trait to his daughter? Can males be carriers of recessive Y-linked traits without expressing them?

Answer 50

No No because the Y-linked traits are carried in only one copy males will always express recessive traits on the Y chromosome Affected father has all affected sons Unaffected father cannot have affected son

Question 51

Do women always express X-linked recessive genes? Do men always express X-linked recessive genes?

Answer 51

No only express them when they are homozygous Yes-they only have one copy Can skip generations SO X LINKED TRAITS AFFECT MEN MORE THAN WOMEN

Question 52

X-linked dominant

Answer 52

Affected fathers have all affected daughters, no affected sons Affected mothers can have unaffected sons or daughters (passes equally to sons and daughters) Does not skip generations

Question 53

Gene pool

Answer 53

Sum total of all genetic information in population

Question 54

Henry Weinberg Law

Answer 54

Frequencies of alleles in the gene pool of a population will not change overtime

Question 55

Assumptions that the Henry Weinberg Law assumes (5)

Answer 55

1. No mutations 2. No migration 3. No natural selection 4. Random mating 5. Large enough pop to prevent random drift in allele frequencies IRL: isn't realistic

Question 56

Henry-weinburg implications at the molecular level

Answer 56

Segregation of alleles, independent assortment and recombination during meiosis can alter the combinations of alleles in gametes but cannot increase or decrease the frequency of an allele in the gametes of one individual or the gametes of the population as a whole

Question 57

p^2 + 2pq + q^2 = 1 where: p^2= 2pq= q^2=

Answer 57

``` p^2= frequency of the GG 2pq= frequency of the Gg q^2= frequency of the gg ```

Question 58

Hardy-weinburg equilibrium

Answer 58

After one generation allele frequencies no longer change