Chapter 10

Question 1

How many chromosomes are in a somatic cell

Answer 1

there are 46 chromosomes or 23 pairs

Question 2

dna makes up…

Answer 2

chromatin which makes up chromosomes

Question 3

chromatin

Answer 3

composed of dna and histones that are packaged into thin stringy fibers; it undergoes further condensation to form chromosome

Question 4

chromosome changes are associated with

Answer 4

dna replication and gene expression

Question 5

(review) gene expression

Answer 5

when heritable information within a gene, the sequence of dna bas pairs, is made into a functional gene product, such as protein or rna

Question 6

histone

Answer 6

helps to package the dna in a compact form to fit within the cell nucleus

Question 7

maternal chromosome ten and paternal chromosome ten are what kinds of chromosomes

Answer 7

Homologous

Question 8

Homologous

Answer 8

same gene (but different versions- example eye gene but maternal can be blue and paternal can be green) , same length, and ..

Question 9

kinetechore

Answer 9

protein complex to which microtubules that separate chromosomes during cell division

Question 10

centromeres

Answer 10

needed for proper segregation of chromosomes; microtubule spindle fibers connect to the centromeres via kinetechores; separate each chromosome into p (top of chromosome) and q (bottom of chromosomes)

Question 11

telomeres

Answer 11

repetitive, non-coding dna sequencing that are found at both ends of a eukaryotic chromosomes; they protect the ends of chromosomes from fusions with each other, degradation, and nucleases

Question 12

nucleases

Answer 12

enzymes that break down dna chromosomes

Question 13

the human karotype

Answer 13

the number and visual appearance of the chromosomes in the cell nuclei of the organism/species

Question 14

when are chromosomes considered indistinguishable from one another

Answer 14

when they are loosely packed because they resemble threads

Question 15

how many chromosomes are non-sex determining chromosomes?

Answer 15

1-44 or 1-22 do not determine the gender of the organism

Question 16

sex determining chromosomes?

Answer 16

23 or 45-46

Question 17

in what way do the sex determining chromosomes differ from each other

Answer 17

male –> XY female –> XX

Question 18

how many genes does the female x chromosome have? male y chromosome?

Answer 18

x has 2000 genes while y has 78

Question 19

what are the majority of the genes found on the y chromosome needed for ?

Answer 19

proper development and sex determination

Question 20

germ cell has how many chromosomes

Answer 20

23

Question 21

cause of down syndrome

Answer 21

47 chromosomes; instead 2 copies of of chromosomes 21 they have 3

Question 22

kerotype analysis

Answer 22

allows us to determine the gender of the organism, abnormal vs normal, # of chromosome and size of them

Question 23

euchromatin vs heterochromatin

Answer 23

euchromatin is non dividing cell and consists of loosely packed dna threads and tightly packed dna threads and is found between the centromeres and telomeres-due to looseness of dna strands dna is expressed and used to make protein; heterochromatin is found in both dividing and non dividing cell; in dividing cell it encompasses the entire chromosome whereas in non dividing cells it is found at the telomeres and centromeres of the chromosomes; here dna is tightly packed.

Question 24

a histone consists of

Answer 24

8 core histans: h2a. h2b, h3, h4, 2h2a, 2h2b, 2h3, 2h4

Question 25

nucleosome

Answer 25

complex of 8 core histones and dna wrapped aroud them

Question 26

Cell Cycle: G0

Answer 26

(only in some cells): not dividing/phase where our mature muscle cells stay permanently --> liver cells spend 6 months in this phase until a signal is received

Question 27

G1 (presynthetic gap)

Answer 27

cell cycle begins; phase in which it cell grows but not divides; it creates organelles for energy while increasing their size.

Question 28

S phase (synthesis)

Answer 28

the cell replicates its genetic material so that each daughter cell will have identical copies (afterwards consists of two identical chromatids that are bound together by a specialized region known as the centromere

Question 29

in the synthesis phase of mitosis how does the number of the chromosomes change

Answer 29

the overall number of sets of chromosomes doesn't change even though the number of chromatid double

Question 30

G2 post-synthetic gap

Answer 30

passes through another quality control checkpoint

Question 31

m stage (mitosis): prophase

Answer 31

involved the condensation of the chromatin into chromosomes; the centriole pairs located within the centrosomes outside of the nucleus separate and move to the opposite poles of the cell to begin forming spindle fibers

Question 32

what are spindle fibers made of

Answer 32

microtubules

Question 33

in prophase what is the centrosome established as

Answer 33

one of two microtubule organizing centers