Chapter 7 Celluar replication and variation

Question 1

Sexual reproduction

Answer 1

offspring produced from two parents
-greater genetic diversity

Question 2

Asexual reproduction

Answer 2

offspring produced from a single parent

Question 3

gamete

Answer 3

sex cell e.g. sperm or egg

Question 4

Locus

Answer 4

position a gene occupies in a chromosome

Question 5

Alleles

Answer 5

Different versions of the same gene (i.e at the same locus) determined by small differences in the DNA sequence of the gene

Question 6

Genotype

Answer 6

Alleles present in the cells of an organism

Question 7

oogonium

Answer 7

Diploid stem cells produced in the embryonic ovary that begin meiosis before birth

Question 8

oocyte

Answer 8

an immature egg cell

Question 9

Spermatogonia

Answer 9

Diploid stem cells in males that undergo mitotic division to produce diploid primary spermatocytes

Question 10

Comparing oogenesis and spermatogenesis

Answer 10

1. In oogenesis, cytokinesis is unequal and produced a single egg while spermatogenesis produced 4 sperm
2. Sperm are produced continuously, whereas oogenesis has long breaks between stages of meiosis

Question 11

Fertilisation

Answer 11

The haploid ovum (n) and sperm (n) fuse to produce a diploid zygote (2n) where in humans, n = 23 and 2n = 46

Question 12

Protein synthesis
There are three main methods to increase genetic diversity.

Answer 12

1. crossing over
2. Independant assortment
3. Random fertilisation

Question 13

Transition from interphase to meiosis

Answer 13

In the last stage of interphase, the cell grows, makes proteins and replicates organelles
-chromatin begins to condense (form into chromosome)

Question 14

cytokinesis

Answer 14

the division into 2 complete cells

Question 14

Meiosis overview

Answer 14

-Prior to meiosis DNA replication occurs (interphase)
-begins with diploid cell and turns into 4 haploid cells

Question 15

Autosomes

Answer 15

chromosome that is the same in both males and females of a species

Question 16

Homologous chromosomes consist of…

Answer 16

-autosomes
-sex chromosomes

Question 17

Sexual reproduction: The role of homologous chromosomes

Answer 17

At fertilisation, each individual receives one of each chromosome from each parent, making a homologous pair

Question 18

diploid

Answer 18

-somatic (body) cells
-46cr

Question 19

Where does meiosis occur

Answer 19

testes and ovaries

Question 20

sex chromosomes

Answer 20

affect sexual traits, different in male and female

homologous: XX
non-homologous: XY

Question 21

Haploid

Answer 21

-sex cells (egg and sperm)
-23n

Question 22

oogenesis

Answer 22

-produces eggs in females
-process in ovary results in the production of female gametes

Question 23

Spermatogenesis

Answer 23

-produces sperm in males
-process in which testes that results in the continuous production of males gametes

Question 24

Independent assortment

Answer 24

-Occurs in metaphase 1 and separates
-Genes are inherited independently of one another
-Paternal + Maternal chromosomes of each pair behave independently

Question 25

Random fertilisation

Answer 25

Meiosis creates genetic variation between gametes through crossing over and independent assortment