Chapter 13: Meiosis and Sexual Life Cycles

Question 1

Heredity

Answer 1

Transmission of traits from one generation to the next

Question 2

Variation

Answer 2

Differences between members of the same species

Question 3

Genetics

Answer 3

Scientific study of heredity and hereditary variation

Question 4

Gene

Answer 4

Discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses)

Question 5

Gamete

Answer 5

Haploid reproductive cell that unites with another haploid reproductive cell to form a zygote

Question 6

Somatic Cell

Answer 6

Any cell in a multicellular organism except a sperm, egg, or their precursors

Question 7

Locus

Answer 7

Specific place along the length of a chromosome where a given gene is located

Question 8

Asexual Reproduction

Answer 8

• Generation of offspring from a single parent that occurs without the fusion of gametes (by budding, division of a single cell, or division of the entire organism into two or more parts
• Offspring are usually identical to the parent

Question 9

Clone

Answer 9

Lineage of genetically identical individuals or cells

Question 10

Sexual Reproduction

Answer 10

Type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from both parents via the gametes

Question 11

Life Cycle

Answer 11

Generation-to-generation sequence of stages in the reproductive history of an organism

Question 12

Karyotype

Answer 12

Display of the chromosome pairs of a cell arranged by size and shape

Question 13

Homologous Chromosomes / Homologs

Answer 13

• Pair of chromosomes of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci
• One is inherited from the organism’s father, the other from the mother

Question 14

Sex Chromosome

Answer 14

Chromosome responsible for determining the sex of an individual

Question 15

Autosome

Answer 15

Chromosome that is not directly involved in determining sex

Question 16

Diploid Cell

Answer 16

Cell containing two sets of chromosomes (2n), one set inherited from each parent

Question 17

Haploid Cell

Answer 17

Cell containing only one set of chromosomes (n)

Question 18

Fertilization

Answer 18

Union of haploid gametes to produce a diploid zygote

Question 19

Zygote

Answer 19

• DIploid cell produced by the union of haploid gametes during fertilization
• Fertilized egg

Question 20

Meiosis

Answer 20

• Modified type of cell division in sexually reproducing organisms
• Two rounds of cell division
• Only one round of DNA replication
• Results in four haploid daughter cells

Question 21

Alternation of Generations

Answer 21

• Life cycle in which there is both a multicellular diploid form (the sporophyte) and a multicellular haploid form (the gametophyte)
• Characteristic of plants and some algae

Question 22

Meiosis I

Answer 22

• First division of a two-stage process

- Results in cells with half the number of chromosome sets as the original cell

Question 23

Meiosis II

Answer 23

• Second division of a two-stage process
• Very similar to mitosis
• Results in four haploid daughter cells

Question 24

Crossing over

Answer 24

Reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis

Question 25

Chiasmata

Answer 25

• X-shaped regions where crossing over occurred earlier in prophase I between homologous sister chromatids
• Become visible after synapsis ends, with the two homologs remaining associated due to sister chromatid cohesion

Question 26

Synaptonemal Complex

Answer 26

• Zipper-like structure composed of proteins

- Connects two homologous chromosomes tightly along their lengths

Question 27

Synapsis

Answer 27

Pairing and physical connection of duplicated chromosomes during prophase I of meiosis

Question 28

Recombinant Chromosome

Answer 28

Chromosome created when crossing over combines DNA from two parents into a single chromosome