definitions

Question 1

Asexual reproduction

Answer 1

Production of offspring without joining of gametes

Question 2

sexual reproduction

Answer 2

Production of offspring by joining gametes

Question 3

gamete

Answer 3

sex cells (sperm and ova)

Question 4

gonad

Answer 4

organs that produce gametes (testes & ovaries)

Question 5

menstruation

Answer 5

Shedding of uterine lining (endometrium) at the start of the menstrual cycle

Question 6

ovulation

Answer 6

release of an ovum from an ovary, normally occurs in the middle of the menstrual cycle

Question 7

fertilisation

Answer 7

Union of ovum and sperm (to form a zygote)

Question 8

implantation

Answer 8

Sinking into the endometrium of an embryo

Question 9

zygote

Answer 9

Fertilised ovum

Question 10

embryo

Answer 10

Early stage of development of a foetus

Question 11

karyotype

Answer 11

An image depicting the full complement of an individual’s chromosomes

Question 12

gene

Answer 12

regions of DNA that code for the production of specific traits.

Question 13

chromsomes

Answer 13

long thin strands of DNA that are located in the nucleus of cells. They contain genes.

Question 14

homologous

Answer 14

Matching (eg homologous chromosomes are matching chromosomes)

Question 15

autosome

Answer 15

chromosomes (other than sex chromosomes) that do not code for gender (eg 1 to 22 in humans)

Question 16

sex chromosome

Answer 16

chromosomes that do code for gender (23rd pair in humans)

Question 17

maternal chromosome

Answer 17

from mother (in ovum)

Question 18

paternal chromosome

Answer 18

from father (in sperm)

Question 19

DNA

Answer 19

Deoxyribonucleic Acid – a double helix shaped chemical that makes up chromosomes

Question 20

nucleotide

Answer 20

building block of DNA

Question 21

nitrogenous base

Answer 21

part of nucleotide – DNA has 4 – Adenine, Thymine, Cytosine, Guanine

Question 22

DNA replication

Answer 22

Copying of DNA to produce a chromosome that consists of 2 chromatids, occurs before cell division

Question 23

chromatid

Answer 23

one strand of a replicated chromosome

Question 24

centromere

Answer 24

part of a duplicated chromosome that holds the chromatids together

Question 25

somatic cells

Answer 25

body cell

Question 26

diploid

Answer 26

full number of chromosomes (eg in humans 46 as in body/somatic cells)

Question 27

haploid

Answer 27

Half number of chromosomes (eg in humans 23 as in gametes)

Question 28

mitosis

Answer 28

nuclear division to produce daughter cells that are identical (for growth and repair)

Question 29

meiosis

Answer 29

nuclear division to produce gametes (reduction division – daughter cells have half the number of chromosomes)

Question 30

cytokinesis

Answer 30

cell division – occurs after nuclear division

Question 31

inheritance

Answer 31

passing of characteristics from one generation to another

Question 32

locus

Answer 32

possession of gene in a chromosome

Question 33

alleles

Answer 33

alternative forms of a gene (eye colour)

Question 34

dominant allele

Answer 34

the trait expressed when heterozygous

Question 35

recessive allele

Answer 35

the trait that is hidden when heterozygous

Question 36

genotype

Answer 36

the combination of alleles present using letters

Question 37

phenotype

Answer 37

the visible affect of the allele combination

Question 38

homozygous

Answer 38

where both identical alleles are present

Question 39

heterozygous

Answer 39

where both alleles are different

Question 40

pedigree

Answer 40

A diagrammatic representation of the inheritance of a trait in a family

Question 41

punnet square

Answer 41

Grid used to summarise predicted allele combinations in offspring

Question 42

complete dominance (inheritance)

Answer 42

Inheritance pattern where the dominant allele completely dominates the recessive allele (gives 2 phenotypes)

Question 43

co-dominance (inheritance)

Answer 43

Inheritance pattern where different alleles are equally expressed (could produce 3 phenotypes)

Question 44

multiple allele (inheritance)

Answer 44

Inheritance pattern where there are more than 2 alleles for a gene (eg ABO blood type)

Question 45

sex (X) linked (inheritance)

Answer 45

Where gene studied is located on the X sex chromosome (not on an autosome)

Question 46

mutations

Answer 46

Changes to the DNA sequence in genes and chromosomes

Question 47

mutagens

Answer 47

Factos that cause changes in DNA. radiation (e.g. ultraviolet radiation, nuclear radiation and X-rays) and some chemical substances (e.g. pesticides, hair dyes, food preservatives and substances in cigarette smoke).

Question 48

gene mutations

Answer 48

Small scale changes to the DNA base sequences within genes.

Question 49

chromosome mutations

Answer 49

Larger scale mutations involving whole extra or missing chromosomes (aneuploidy), or large sections of chromosomes being translocated or deleted.

Question 50

traits

Answer 50

characteristics