genetic Diversity

Question 1

haploid

Answer 1

one copy of each chromosome in a cell

Question 2

diploid

Answer 2

two copies of each chromosome in a cell

Question 3

meiosis

Answer 3

cell division that creates genetically different gametes
there are two nuclear divisions in this process
results in four haploid daughter
cells

Question 4

independent segregation

Answer 4

homologous pairs of chromosomes randomly line up opposite each other at the equator of the cell
when they separate it creates a
large number of possible
combinations of chromosomes
in the daughter cells produced

Question 5

crossing over

Answer 5

homologous pairs of chromosomes line up opposite each other at the equator in meiosis 1
parts of the chromatids twist, break and recombine with another chromatid
results in new combinations of alleles in the gametes

Question 6

How does meiosis introduce variation

Answer 6

Crossing over
Independent segregation

Question 7

Types of gene mutations

Answer 7

Deletion
Substitution

Question 8

What is a frame shift

Answer 8

The removal of one base
Changes all subsequent codons
All bases shift back one position

Question 9

Chromosome mutation

Answer 9

Change in the number of chromosomes
Occurs during meiosis

Question 10

Deletion mutation

Answer 10

A gene mutation
a base is removed from a sequence
causes a frameshift

Question 11

Substitution mutation

Answer 11

a gene mutation
a base is swapped for a different one

Question 12

Non-disjunction

Answer 12

The chromosomes or chromatids dont split equally during anaphase

Question 13

Polyploidy

Answer 13

changes in whole sets of chromosomes
e.g. when organisms have three
or more sets of chromosomes
mainly occurs in plants

Question 14

Aneuploidy

Answer 14

a change in the number of individual chromosomes
e.g 3 copies of chromosome 21

Question 15

Downs syndrome

Answer 15

causes by a chromosome mutation
an example of aneuploidy
3 copies of chromosome 21

Question 16

Genetic diversity

Answer 16

The measure of how many different alleles there are for each gene

Question 17

Gene mutations

Answer 17

a change in the base sequence of DNA
substitution or deletion

Question 18

When in the cell cycle do gene mutations occur

Answer 18

Interphase (s phase)
this is when DNA is replicated

Question 19

Natural selection

Answer 19

the process that leads to evolution in populations
results in species becoming better adapted to their environment

Question 20

Gene pool

Answer 20

All the genes and alleles in a population at a particular time

Question 21

Allele frequency

Answer 21

the proportion of organisms within the population carrying a particular allele

Question 22

Evolution

Answer 22

the change in allele frequency over many generations in a population

Question 23

Selection pressure

Answer 23

factors that affect the survival of an organism
the driving force of natural selection

Question 24

Types of selection

Answer 24

Stabilising
Directional

Question 25

Directional selection

Answer 25

one of the extreme traits has a selective advantage
occurs when there is a change in the environment
the modal trait changes

Question 26

Stabilising selection

Answer 26

the middle (median) trait has a selective advantage and continues to be the most frequent in the population
represented by a normal distribution graph
range decreases as the extreme
traits are lost over time

Question 27

Example of directional selection

Answer 27

Abiotic resistance

Question 28

Example of stabilising selection

Answer 28

Human birth weight