Ch. 3

Question 1

Mitosis

Answer 1

cell growth, repair, asexual division
2N -> 2N, 2N (diploid)
N= 23 (human)

Question 2

Meiosis

Answer 2

sexual reproduction (sperm & eggs)
2N -> N, N, N, N (haploid)
N= 23 (human)

Question 3

Gametes

Answer 3

sperm & oocytes

Question 4

Gonads

Answer 4

paired structures (testes & ovaries)

Question 5

Semen

Answer 5

5% sperm + 95% seminal fluid (from seminal vesicle)

Question 6

Vas deferens

Answer 6

rapid transport of sperm

Question 7

Epididymis

Answer 7

sperm complete maturation

Question 8

Testis

Answer 8

contains sperm-producing seminiferous tubules and cells that secrete testosterone and other hormones

Question 9

Meiosis

Answer 9

Homologous pairs have the same genes in the same order but CARRY DIFFERENT ALLELES (variants) of the same gene

gametes are haploid & somatic cells are diploid for each chromosome

Question 10

Mitosis

Answer 10

• occurs in body cells
• divides ONCE
• creates TWO cells
• identical

Question 11

Meiosis

Answer 11

• occurs in gametes cells
• divides TWICE (meiosis I & II)
• creates 4 cells
• NOT genetically identical
• increases genetic diversity

Question 12

Spermatogenesis

Answer 12

spermatogonium (diploid) - primary spermatocytes (diploid) - meiosis I - secondary spermatocytes (half of diploid #) - meiosis II - acrosome/spermatid (haploid)- sperm accumulate in center (haploid)

Question 13

Sperm Structure

Acrosome

Answer 13

enzymes to digest surface of egg (in sperm head)

Question 14

Sperm structure

Head

Answer 14

DNA in enzyme-rich cap

Question 15

Sperm Structure

Nucleus

Answer 15

In sperm head

Question 16

Sperm Structure

Spiral Mitochondria

Answer 16

energy to swim
in midpiece

Question 17

Sperm Structure

Tail

Answer 17

flagella w/ core of microtubules

Question 18

Oogenesis

Answer 18

Oogonium (diploid) - primary oocyte (diploid) - meiosis I - secondary oocyte OR first polar body may divide (half of the diploid #) - meiosis II (if fertilization occurs) - ovum (egg) & second polar body (haploid) OR polar bodies die - mature egg

Question 19

During ovulation period, is the ovum primary or secondary?

Answer 19

Secondary

Question 20

Meiosis I

Answer 20

• homologous chromosomes form pairs
• the # of replicated chromosomes is halved
• two daughter cells are formed
• crossing over occurs

Question 21

Meiosis II

Answer 21

• 4 daughter cells formed
• sister chromatids separate

Question 22

Spermatogenesis

Answer 22

• an acrosomal region must be present in mature cells
• 4 gametes are produced that could contribute to zygote
• a mitochondria- containing midpiece must be present in mature cells

Question 23

Oogenesis

Answer 23

• one gamete is produced
• meiosis is completed only if fertilization occurs
• polar bodies are formed

Question 24

Oocyte

Answer 24

the largest human cell

Question 25

A Woman's Biological Clock

Answer 25

Birth (about 1mil follicles) - Menopause (less than 10k), # of follicles drop at each milestone (birth, puberty, most fertile @ 20, fertility decline @ 35, not healthy oocytes start, menopause) 1 egg per follicle

Question 26

Fertilization

Answer 26

- fusion of oocyte & sperm - formation of zygote (fertilized egg) - formation of blastocyte by cell division (implant to wall of uterus) - inner cell mass form cells of fetus (embryonic stem cells) - trophoblast form support structures for fetus (placenta)

Question 27

Pregnancy

Answer 27

First trimester- organ formation Second trimester- organ maturation Third trimester- rapid growth

Question 28

Zygote

Answer 28

two genetic packages meet & merge

Question 29

A species has a diploid number of 36. Without meiosis, the gametes would each contain _________blank chromosomes, and the fertilized ovum would have _________blank chromosomes.

Answer 29

36; 72

Question 30

How many sex chromosomes does a human sperm or egg contain? How many autosomes?

Answer 30

1; 22

Question 31

What is the molecular mechanism underlying most accelerated aging conditions?

Answer 31

Inadequate DNA repair

Question 32

Ovulation to Implantation

Answer 32

Day 0: ova duct, ovulated secondary oocyte - fertilization - zygote- uterine tube Day 1: meiosis Day 2: 2 cells Day 3: 4 cells Day 4: Morula (can divide into multiple for twins) Inner Cell Mass Day 7: blastocyst implants (abortion pills thin uterine wall) - embryo

Question 33

Monozygotic twins

Answer 33

Identical; single fertilized ovum, 3 types can form depending on when fertilized ovum or when embryo splits , exposed to slightly different uterine environments

Question 33

Dizygotic Twins

Answer 33

Fraternal; two sperm fertilize two oocytes, same genetic relationship as any 2 siblings

Question 33

Organogenesis

Answer 33

transformation of the simple three germ layers into distinct organs

Question 33

Fetus growth

Answer 33

soft cartilage to bones, nerve and muscle functions become coordinated, wk 6 = anatomical differences (SRY gene expressed in males), wk 12 = kicks, faces, fists, sucks thumb, 4 month = fetus has hair, eyebrows, etc

Question 34

Teratogens

Answer 34

chemical or other agents that cause birth defects

Question 34

Is longevity inherited?

Answer 34

Centenarians have inherited 2 types of gene variants- those that directly protect them and wild type alleles of genes that when mutated causes diseases (complex traits)