Meiosis and Sexual Life Cycles (Chapter 13)

Question 1

Genetics

Answer 1

Scientific study of heredity and variation

Question 2

Heredity

Answer 2

transmission of traits from one generation to the next

Question 3

Variation

Answer 3

demonstrated by differences in appearance that offspring show from parents and siblings

Question 4

Genes

Answer 4

Units of heredity, made of segments (Locus or Loci) of DNA

Question 5

Gametes

Answer 5

Reproductive cells responsible for passing genes to the next generations.

Question 6

Locus/ Loci

Answer 6

specific location of a gene on certain chromosomes.

Question 7

Asexual reproduction

Answer 7

Single individual passes genes to offspring without fusion of gametes.

Question 8

Clone

Answer 8

Group of genetically identical individuals from same parent.

Question 9

Sexual reproduction

Answer 9

two parents give rise to offspring with unique combinations of genes inherited from the two parents.

Question 10

Life cycle

Answer 10

generation-to-generation sequence of stages in reproductive history of organisms.

Question 11

Somatic cells

Answer 11

Any cell other than gametes.

Question 12

23

Answer 12

pairs of chromosomes possessed by normal humans

Question 13

Karyotype

Answer 13

ordered display of pairs of chromosomes.

Question 14

Homologous chromosomes

Answer 14

two matching chromosomes.

Question 15

Sex chromosomes

Answer 15

determine the sex of individual (eg XY)

Question 16

Autosomes

Answer 16

chromosomes that do not determine sex

Question 17

Diploid cell

Answer 17

2n has two sets of chromosomes.

Question 18

Haploid

Answer 18

n a single set of chromosomes (like gametes)

Question 19

Fertilization

Answer 19

union of gametes.

Question 20

Zygote

Answer 20

fertilized egg, has one set of chromosomes from each parent.

Question 21

Meiosis

Answer 21

produces Gametes

Question 22

Meiosis I

Answer 22

(reductional division): homologs pair up and separate, resulting in two haploid daughter cells with replicated chromosomes.

Question 23

Meiosis II

Answer 23

(equational division): sister chromatids separate.

Question 24

Prophase I

Answer 24

(90% of required meiosis time) Chromosomes begin to condense

Question 25

Synapsis

Answer 25

Homologous chromosomes loosely pair up, aligned gene by gene.

Question 26

Crossing over (only in Prophase)

Answer 26

non sister chromatids exchange DNA segments

Question 27

tetrad

Answer 27

group of four chromatids.

Question 28

Chiasmata

Answer 28

X shaped regions where crossing over occurs

Question 29

Metaphase I

Answer 29

Tetrades line up at metaphase plate, microtubules attach to kinetochores of one chromosome.

Question 30

Anaphase I

Answer 30

Pairs of homologus chromosomes separate pulled toward each pole guided by spindle apparatus.

Question 31

Telophase I and Cytokinesis

Answer 31

Cleavage furrow (animals) or cell plate forms (plants), no replication occurs between Meiosis I and II

Question 32

Prophase II

Answer 32

Spindle apparatus forms, Chromosomes move toward metaphase plate.

Question 33

Metaphase II

Answer 33

sister chromatids align and kinetochores attach to chromatids.

Question 34

Anaphase II

Answer 34

Sister chromatids separate and move toward opposite poles.

Question 35

Telophase II and Cytokinesis

Answer 35

Nuclei forms and chromosomes begin decondensing, cytoplasm separates, 4 genetically distinct haploid daughter cells formed.

Question 36

recombinant chromosomes

Answer 36

(crossing over) combined DNA inherited from each parent.

Question 37

Random Fertilization

Answer 37

the idea that it’s impossible to tell which gametes will combine with each other in sexual reproduction.