genetics and variation

Question 1

How are inherited features passed on?

Answer 1

Through genetic material

Question 2

Are all features inherited?

Answer 2

No, some like the language you speak is based on your environment.

Question 3

What is a gene?

Answer 3

Genes are tiny parts of chromosomes.

Question 4

What do genes do?

Answer 4

They control a specific characteristic.

Question 5

How many genes are there?

Answer 5

There are many genes on each chromosome but around 20,000.

Question 6

What do chromosomes do and where are they found?

Answer 6

They carry the genetic material located in the nuclei of the cell.

Question 7

What are chromosomes matched in?

Answer 7

Pairs

Question 8

What does a nucleus do and contain?

Answer 8

The nucleus is the control centre of the cell. It contains long strands of genetic information.

Question 9

What are chromosomes and genes made of?

Answer 9

Chromosomes and genes are made of DNA. Each chromosome is a very long molecule of tightly coiled DNA.

Question 10

What do DNA molecules carry?

Answer 10

Carries the code that controls what cells are made of and what they do.

Question 11

What are alleles?

Answer 11

Different forms of a gene. Blue eyes and brown eyes are under the control of different alleles.

Question 12

What is the DNA backbone?

Answer 12

Two strands that form the uprights of the DNA ladder. Support the base pairs but don’t contain genetic information.

Question 13

What is the spiral shape of DNA called?

Answer 13

A double helix

Question 14

What are the bases of DNA?

Answer 14

Chemical units that carry genetic information.

Question 15

What do base pairs do?

Answer 15

Keep the 2 strands of a DNA molecule together

Question 16

How is genetic info transmitted to the offspring?

Answer 16

One sex cell from each parent fuses together, making 1 cell with DNA from both parents.

Question 17

How many chromosomes do human body cells contain?

Answer 17

46, in 23 pairs

Question 18

How many chromosomes do egg and sperm cells contain?

Answer 18

23 each, which is half the number in body cells

Question 19

When egg and sperm cells fuse together what happens?

Answer 19

The nuclei fuse together and it is called fertilisation, producing a fertilised egg cell.

Question 20

What is continuous variation?

Answer 20

Variation with no limit for the population. Use a line graph

Question 21

What is discrete variation?

Answer 21

Variation with distinct groups. Use a bar chart

Question 22

What is evolution?

Answer 22

Change in heritable characteristics of a population over time.

Question 23

How does evolution occur?

Answer 23

In a process called natural selection

Question 24

What does natural selection explain?

Answer 24

How species change over time as a result of difference in characteristics and survival rates of individuals

Question 25

Key features of natural selection

Answer 25

variation, competition, selection bc of advantage, survival of the fittest, breeding, inheritance

Question 26

What does natural selection cause?

Answer 26

Evolution

Question 27

What is speciation?

Answer 27

New species evolving from earlier ones as a result of natural selection

Question 28

What are fossils?

Answer 28

Fossils are the remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form

Question 29

What is petrified form?

Answer 29

When minerals replace the structure of an organism

Question 30

Different types of fossils

Answer 30

3 types; impression fossils, preserved organisms and mineral replacement

Question 31

How can you show dominant and recessive alleles?

Answer 31

punnet squares or genetic cross diagram

Question 32

What is amber?

Answer 32

Pre-historic remains of tree resin

Question 33

Process of fossils

Answer 33

animal death, sediment thickens, skeleton dissolves, minerals crystallise, fossil exposed

Question 34

Things that living organisms compete for

Answer 34

food, territory, water, mates, space, light, mineral ions

Question 35

One way of telling if animals are different species

Answer 35

If their babies are infertile eg liger

Question 36

What is a species?

Answer 36

A group of organisms that have characteristics in common and can interbreed to produce fertile offspring

Question 37

Can there be variation in species?

Answer 37

Yes

Question 38

What is genetic variation caused by?

Answer 38

Your genes

Question 39

What is a mutation?

Answer 39

A change in the genes

Question 40

What is extinction?

Answer 40

When no individuals of a species remain

Question 41

Causes of extinction

Answer 41

quick environment change (habitat destruction), new predator/disease, competition with new species for food, catastrophic event (tsunami)

Question 42

genotype

Answer 42

the 2 alleles that an organism has eg pp or Pp etc

Question 43

heterozygous

Answer 43

2 different types of allele eg Aa

Question 44

homozygous

Answer 44

2 copies of the same allele eg aa

Question 45

phenotype

Answer 45

physical appearance due to your genotype

Question 46

vertebrate

Answer 46

animals with a backbone

Question 47

invertebrate

Answer 47

animals without a backbone

Question 48

how many chromosomes are there

Answer 48

23 pairs

Question 49

dominant

Answer 49

gene which shows up

Question 50

recessive

Answer 50

gene which doesn’t show up