Chapter 2

Question 1

what are characteristics of a model organism?

Answer 1

small
maintained easily
large progeny numbers
short generation time
small genome
representative
varied available traits

Question 2

what is Autosomal variation?

Answer 2

phenotypic differences from genes on regular chromosomes (autosomes).

Question 3

what is Sex-linked inheritance?

Answer 3

phenotypic differences from genes on sex chromosomes.

Question 4

que est pure lines?

Answer 4

there is no gene or phenotype variation in a line over generations.

Question 5

what are crosses?

Answer 5

a way to introduce traits/genes from one variety or line into a new one.
eg selfing / cross pollination

Question 9

what is Cytoplasmic inheritance?

Answer 9

phenotypic differences from genes on organellar chromosomes.

Question 10

What is ploidy

Answer 10

The amount of gene copies an organism has.

Question 11

Types of ploidy

Answer 11

Haploid- n
Diploid- 2n
Tetraploid- 4n
Hexaploid- 6n
Dodecaploid- 12n

Question 12

What are the types of cellular division

Answer 12

Meiosis- makes gamets through reductional cell division
Mitosis- makes identical cell copies (errors still happen)

Question 13

What are the cell cycle stages?

Answer 13

M- mitosis/ meiosis
G1- gap 1
S- DNA synthesis
G2- gap 2

Question 14

Explain the S phase

Answer 14

DNA synthesis makes identical DNA molecules via replication- sister chromatids.
DNA content is doubled.
The number of chromosomes stays the same but each chromosome has 2 sister chromatids (dyads).

Question 15

Stages of mitosis

Answer 15

Interphase- 2n,
Prophase- supercoiling of DNA strands. Sister chromatids become joined at centeomere. Breakdown of nuclear membrane amd formation of spindle fibers.

Question 16

Stages of meiosis

Answer 16

Interphase.
Prophase-
-leptotone-

Question 17

What is the difference between mitosis and meiosis

Question 18

What is kinetochore?

Answer 18

Multiprotein complex that binds to centromere.

Question 19

What is a null allele (mutation)?

Answer 19

No functioning gene product formed

Question 20

What is a leaky allele (mutation)?

Answer 20

Some functional gene product.

Question 21

What is a silent allele (mutation)?

Answer 21

No change in gene product

Question 22

What is an intron?

Question 23

What is an exon?

Question 24

Describe mutant alleles.

Answer 24

Thay may be recessivev(more common) or dominant (less common).

Question 25

What is haplosufficient?

Answer 25

When 1 wild-type alleleis enough to show the wild type phenotype.
If mutated the mutation is recessive.

Question 26

What is haploinsufficient?

Answer 26

When 1 wild-type alleleis not enough to show the wild type phenotype.
If mutated the mutation is dominant.

Question 27

What are characteristics of autosomal recessive traits?

Question 28

What are characteristics of autosomal dominant traits?

Answer 28

Phenotype appears in each generation

Question 29

What are autosomal traits?

Question 30

What is an inconsistent inheritance pattern?

Answer 30

They are the reasons why some pedigree analysis don’t make sense.

Question 31

What are types of inconsistent inheritance pattern?

Answer 31

Expressivity- degree to which the trait expression differs among individuals.

Penetrance- proportion of genotypes that show expected genotype.

Question 32

Some characteristics of X-linked recessive traits are…

Answer 32

Phenotype more common in males.
Affected fathers hv no affected kids.
Trait passed from grandfather to grandchildren.

Question 33

Some characteristics of X-linked dominant traits are…

Answer 33

Father’s pass trait to all daughters but no sons
Mother’s pass trait to 1/2 sons and daughters.

Question 34

What is X-chromosome inactiveion?

Answer 34

Permanent deactivation of one x chromosome in all cells except eggs.
It doesn’t happen in the egg cell maker.
In somatic cells, they pick and choose which chromosome is activated

Question 35

What is a barr body?