Science Reproduction and genetics

Question 1

DNA

Answer 1

A chromosome that carries the genetic instructions

Question 2

Gene

Answer 2

A molecule that codes for one trait e.g eye color

Question 3

Allele

Answer 3

Different forms of genes e.g blue eyes

Question 4

Chromesome

Answer 4

Long thread-like structures that contain long-lengths of DNA that hold many genes

Question 5

Asexual vs sexual reproduction

Answer 5

Asexual- Does not involve the fusion of two gametes and is a new offspring by a single parent

Sexual- fusion of two gametes and is the the offspring of two parents

Question 6

State how many chromosomes are found in human gametes and body cells

Answer 6

43 chromosome
23 gametes

Question 7

Discuss the importance of halving the chromosome number in gametes

Answer 7

Otherwise it will double in every new generation which is not right life process. It leads to death and genetic diseases.

Question 8

Label a diagram showing the processes from cell division and fertilisation to foetus, including the chromosome number at each stage (cell division, fertilisation, sperm, egg, zygote, embryo, foetus)

Answer 8

book

Question 9

Distinguish between the terms dominant and recessive, phenotype and genotype, homozygous and heterozygous

Answer 9

Dominant: An allele that expresses its trait even when only one copy is present.
Recessive: An allele that expresses its trait only when two copies are present
Phenotype: The physical expression of the gene
Genotype: The alleles an individual has for a trait

Homozygous: An organism that has two identical alleles for a specific gene
Heterozygous: An organism that has two different alleles for a specific gene

Question 10

Use Punnett squares to carry out simple monohybrid crosses

Answer 10

book

Question 11

Use Punnett squares to predict phenotype ratios

Answer 11

book

Question 12

Explain the process of natural selection

Answer 12

organisms who are better adapted to their environment survive and produce more offspring