4.3 Meiosis: Sexual Reproduction

Question 1

Benefits of sexual reproduction

Answer 1

Offspring are not genetically identical to parents or to each other
Variability in offspring means that if the environment changes, some of the offspring are better adapted and survive.

Question 2

Processes in Sexual Reproduction

Answer 2

Formation of gametes, which are haploid sex cells
Fertilization, when gametes meet and form a zygote.

Question 3

Gene

Answer 3

Code for a trait: Hair colour

Question 4

Allele

Answer 4

The variation that you posses: red, brown, blond, black hair

Question 5

Meaning of capital letters in alleles

Answer 5

A indicate a dominant allele
This means it will show up

Question 6

Meaning of lowercase letters in alleles

Answer 6

a indicate a recessive allele
This means it only shows up if the dominant is not present

Question 7

Phenotype

Answer 7

Physically represents the outward appearance of the individual according to their genotype

Question 8

Genotype

Answer 8

genetic makeup of the individual: which genes they possess.

Question 9

Meiosis

Answer 9

The process by which these alleles are separated into the gametes
Sexual reproduction depends on meiosis
It is a process involving two stages in which the resulting daughter cells have half the number of chromosomes (haploid) as the parent cell
Results in the formation of haploid sex cells (eggs & sperm)

Question 10

Law of Segregation

Answer 10

Each parent passes one, and only one, allele to their offspring.
Since a pair of chromosomes carries two alleles, only one chromosome can be passed along.
Hence why there is a need for diploid cells to become haploid

Question 11

Random Assortment

Answer 11

The number of possible combinations of chromosomes depends on the chromosome pairs, for diploid (2n) organisms the number of possible combinations is 2n

Question 12

Law of Independent Assortment

Answer 12

The inheritance of one particular pair of genes (or one chromosome) does not affect the inheritance of any other pair of genes (or chromosomes).
In other words, each chromosome is a coin flip. They cannot influence the movement of other chromosomes.

Question 13

Gametogenesis

Answer 13

Spermatogenesis produces sperm and oogenesis produces eggs
In oogenesis, cytoplasm does not split evenly between eggs
Cells that do not receive enough cytoplasm are called polar bodies, and die off.
One oocyte (egg cell) is produced

Question 14

Male sex chromosomes

Answer 14

XY

Question 15

Female sex chromosomes

Answer 15

XX