Inheritance, variation and evolution (p2)

Question 1

sexual reproduction

Answer 1

a process which involves the fusion of male and female gametes

Question 2

what cells are involved in sexual reproduction in animals

Answer 2

sperm and egg cells

Question 3

what cells are involved in sexual reproduction in plants

Answer 3

pollen and egg cells

Question 4

what is asexual reproduction

Answer 4

a process which involves only one parent, only mitosis is involved- produces clones

Question 5

way to remember mitosis

Answer 5

MITosis =Making Identical Two

Question 6

what is meiosis

Answer 6

when cells divide to form gametes (have half the number of chromosomes as body cells)

Question 7

what happens during meiosis

Answer 7

-cell makes copies of its genetic info,
-cell divides twice to form 4 gametes , each with a single set of chromosomes
- all gametes are genetically different from each other

Question 8

what are gametes

Answer 8

an organisms reproductive (sex) cells, which have half the usual genetic info

Question 9

what are female gametes called in animals

Answer 9

ova/egg cells

Question 10

what are male gametes called in animals

Answer 10

sperm

Question 11

what is DNA

Answer 11

the chemical that a cells genetic info is composed from. it is a polymer, made up of two strands forming a double helix

Question 12

where is DNA found

Answer 12

organised into chromosomes in the nucleus

Question 13

what is a gene

Answer 13

a small section of DNA on a chromosome

Question 14

what is a genome

Answer 14

all of the genetic material of an organism

Question 15

what is an allele

Answer 15

one of two or more versions of a gene

Question 16

what are recessive alleles

Answer 16

only expressed if two copies are present

Question 17

what are dominant alleles

Answer 17

always expressed, even if only one copy is present

Question 18

heterozygous

Answer 18

a gene that has two different alleles

Question 19

homozygous

Answer 19

a gene that has two identical alleles

Question 20

is polydactyly caused by dominant or recessive allele

Answer 20

dominant

Question 21

is cystic fibrosis caused by dominant or recessive allele

Answer 21

recessive

Question 22

how many pairs of chromosomes do ordinary human body cells contain

Answer 22

23 pairs

Question 23

how many chromosomes do human gametes have

Answer 23

23 (23 ONLY not 23 pairs)

Question 24

sex chromosomes in females

Answer 24

XX

Question 25

sex chromosomes in males

Answer 25

XY

Question 26

what is a species

Answer 26

a group of similar organisms which can interbreed to produce fertile offspring

Question 27

what is variation

Answer 27

differences in the characteristics of individuals of a population

Question 28

what are mutations

Answer 28

random alterations in DNA which occur continuously

Question 29

what is evolution

Answer 29

the inherited characteristics of populations over successive generations

Question 30

what is selective breeding

Answer 30

when humans breed plants and animals for particular genetic characteristics.

Question 31

What has selective breeding been used to produce?

Answer 31

* Disease resistance in food crops * Animals which produce more meat or milk * Domestic dogs with a gentle nature * Large or unusual flowers.

Question 32

What is the main drawback of selective breeding?

Answer 32

Leads to inbreeding, where organisms are particularly prone to inherited defects and disease (a disease that can kill one can likely kill them all).

Question 33

What is genetic engineering?

Answer 33

when the genome of an organism is changed, by introducing a gene from another organism

Question 34

What has genetic engineering been used to produce?

Answer 34

* Plant crops that are resistant to diseases * Plant that produce more flowers or fruit/veg * Bacterial cells that produce useful substances, such as human insulin

Question 35

What are fossils?

Answer 35

The remains of organisms from millions of years ago, embedded in rocks.

Question 36

Why is the fossil record incomplete?

Answer 36

Many early forms of life were soft-bodied, so few fossils formed, and they have been destroyed over time

Question 37

What can be learned from fossils?

Answer 37

How much different organisms have changed as life developed on Earth.

Question 38

What is extinction?

Answer 38

when there are no remaining individuals of a species still alive

Question 39

Why can bacteria evolve rapidly?

Answer 39

Because they reproduce at a high rate

Question 40

How can a strain of bacteria become resistant to an antibiotic?

Answer 40

* Mutations of bacteria produce new strains * Some strains may be resistant to antibiotics, and so are not killed * These ones survive and reproduce * The resistant strain will then spread

Question 41

Give an example of an antibiotic-resistant bacterium.

Answer 41

MRSA

Question 42

What can and should be done to reduce the rate of development of antibiotic resistant strains?

Answer 42

* Doctors should not prescribe antibiotics inappropriately * Patients should complete their course of antibiotics * Antibiotics shouldn't be used too much on farms

Question 43

Why is antibiotic resistance such a big problem?

Answer 43

The development of new antibiotics is expensive and slow

Question 44

How did Linnaeus classify living things?

Answer 44

Kingdom Phylum Class Order Family Genus Species

Question 44

What are the three domains in the 'three-domain system' of classification of living organisms?

Answer 44

* Archaea (simple bacteria, usually living in extreme environments) * Bacteria (true bacteria) * Eukaryota (includes protists, fungi, plants and animals).

Question 45

Who developed the 'three-domain system' of classification of living organisms?

Answer 45

Carl Woese