Chap 2 : Introduction to the human genome

Question 1

Purines

Answer 1

• Adenine (A)
• Guanine (G)

Question 2

Pyrimidines

Answer 2

• Thymine (T)
• Cytosine (C)

Question 3

What is chromatin

Answer 3

Genomic DNA + specialized protiens (histones and non-histones)

Question 4

Number of base pairs associated with each histone?

Answer 4

140

Question 5

number of genes in the mitochondrial DNA

Answer 5

37 genes

Question 6

% of variation between any two individuals?

Answer 6

0.5%

Question 7

the period between two successive mitosis?

Answer 7

Interphase

• Where a cell spends most of it’s life
• consist of G1, S, G2
• chromosomes are easy to see under a light microscope
• 46 chromosomes

Question 8

Cells can stay in this phase for hours years or days depending on the cell?

Answer 8

G1

No DNA synthesis takes place

Phase immediatly after mitosis

Question 9

Liver cells can enter this phase then return to G1 after organ damage

Answer 9

G0

Question 10

mitosis

Condensation of chromosomes

formation of cetrosomes

Answer 10

Prophase

Question 11

Nuclear membrane disolves

Answer 11

prometaphase

Question 12

chromosomes line up at the equtorial plane

Answer 12

Metaphase

Question 13

mitosis

chromosomes separate

form independent daughter chromosomes

Answer 13

Anaphase

Question 14

mitosis

reformation of nuclear membrane

decondence chromosome

Answer 14

Telephase

Question 15

Place where two sister chromatids are connected

Answer 15

centromere

Question 16

formation of sister chromatids and a 2nd centrosome

Answer 16

S phase

synthesis phase

Question 17

reduction division

stage of recombination

Answer 17

Meiosis I

prophase I

Question 18

meiosis: end of interphase

number of chromosomes

number of sister chromatids

Answer 18

• 46 chromosomes
• 92 sister chromotaids

Question 19

stage of homologous recombination

Answer 19

prophase I

(pachytene)

Question 20

meiosis

nuclear membrane dissapears

spindle forms

paired chromosomes (tetrads) line up

Answer 20

metaphase I

Question 21

meiosis

homologous pairs pull apart

Answer 21

Anaphase I

(sister chromatids ARE NOT pulled apart)

Question 22

meiosis

cytokenesis occurs

2 new daughter cells - haploid

genetically different from parent cell

Answer 22

Telophase I

Question 23

When is the diploid chromosome number restored? When is the two-chromatid structure of a typical metaphase chromosome restored?

Answer 23

• At fertilization
• During S phase of the next cell cycle

Question 24

Sperm (spermatozoa) are formed after ______ _______ is reached?

Answer 24

• Sexual maturity

Question 25

Primary spermatocyte are ________ germ cells

Answer 25

Diploid

Question 26

What male germ cells are present at the end of meiosis I

Answer 26

• Secondary spermatocytes
• 23X, 23Y

Question 27

When does oogenesis begin?

Answer 27

during a females development as a fetus

Question 28

What phase of meiosis is the primary oocyte suspended in?

Answer 28

• Primary oocytes are suspended in Prophase I until sexual maturity

Question 29

when does the oocyte complete meiosis I

Answer 29

• Before ovulation
• formation of the secondary oocyte and 1st polar body

Question 30

What stage of meiosis is the oocyte halted after ovulation

Answer 30

• The secondary oocyte is halted in metaphase of meiosis II after ovulation

Question 31

When does completion of meiosis II occur in the oocyte

Answer 31

• Completion of meiosis II occurs after fertilization and formation of the 2nd polar body