Inheritance, variation and evolution

Question 1

allele

Answer 1

an alternative form of a gene

Question 2

asexual reproduction

Answer 2

production of offspring from a single parent by mitosis, the offspring are clones of the parent

Question 3

chromosome

Answer 3

structures that contain dna of an organism and are found in the nucleus

Question 4

cystic fibrosis

Answer 4

a disorder of cell membranes caused by a recessive allele

Question 5

dna

Answer 5

a polymer that is made up of two strand that form a double helix

Question 6

dominant

Answer 6

an allele that is always expressed, even if only one copy is present

Question 7

fertilisation

Answer 7

the fusion of male and female gametes

Question 8

gamete

Answer 8

sperm and egg cell in animals; pollen and egg cell in plants

Question 9

gene

Answer 9

small section of dna that codes for a specific protein

Question 10

genome

Answer 10

entire genetic material of an organism

Question 11

heterozygous

Answer 11

a genotype that have 2 different alleles - one recessive and one dominant

Question 12

genotype

Answer 12

combination of alleles

Question 13

homozygous

Answer 13

a genotype that has two of the same alleles, either two dominant or two recessive alleles

Question 14

meiosis

Answer 14

the two stage process of cell division that reduce the chromosome number of the daughter cells, making gametes for sexual reproduction

Question 15

mutation

Answer 15

change in dna

Question 16

polydactyly

Answer 16

an allele that is only expressed if two copies of it are present

Question 17

recessive

Answer 17

an allele that is only present of two copies of it are both present

Question 18

sexual reproduction

Answer 18

production of offspring by combining the genetic information from gametes of two parent, leads to variation in the offspring

Question 19

mitosis key points

Answer 19

• produces 2 IDENTICAL daughter cells
• the cell divides ONCE
• Chromosome number of the daughter cells is the same as the parent cells
• used for growth, repair and asexual reproduction

Question 20

meiosis key points

Answer 20

• produces FOUR NOT GENETICALLY IDENTICAL daughter cells
• cell divides TWICE
• The chromosome number is reduced by half
• Produced gametes for sexual reproduction

Question 21

Sex determination on females

Answer 21

females carry two X chromosomes

Question 22

Sex determination on males

Answer 22

males carry one X and one Y chromosome

Question 23

embryo screening

Answer 23

genetic test carried out on an embryo to see whether it carries a faulty allele

Question 24

evolution

Answer 24

a change in the inherited characteristics of a population, over time, through a process of natural selection

Question 25

evolutionary tree

Answer 25

a method used to show how scientists believe organisms are related

Question 26

extinction

Answer 26

the permanent loss of all members of species

Question 27

fossils

Answer 27

the remains of organisms from millions of years ago which are found in rocks

Question 28

genetic engineering

Answer 28

the process by which scientists manipulate and change the genotype of an organisms

Question 29

natural selection

Answer 29

process by which organisms that are better suited to an environment are more like to survive and reproduce

Question 30

selective breeding

Answer 30

humans selecting animals or plant, that have a required characteristic, for breeding

Question 31

speciation

Answer 31

process by which two species evolve from a single original species by natural selection. But these two populations are so different that they cannot interbreed and produce fertile offspring

Question 32

variation

Answer 32

differences in characteristics of individuals in a population

Question 33

why would a species evolve

Answer 33

- if a characteristic is advantageous in an environment, they will be able to compete better - - meaning that they will be more likely to survive and produce offspring - their offspring will inherit the advantageous allele

Question 34

fossils could be...

Answer 34

- actual remains that have not decayed - mineralised forms of the harder parts of an organism, such as bones - traces of organisms such as footprints in mud

Question 35

why do we have little evidence of early life forms

Answer 35

many organisms were soft bodied so left little trace

Question 36

what do fossils do

Answer 36

help us understand how much or little organisms have changed as life developed on earth

Question 37

how to carry out selective breeding

Answer 37

- choose parent with desired characteristic - select offspring with best characteristic shown and breed to make next generation - these offspring are then bred again and again, over many generation until desired result is achieved

Question 38

how to remember classification by Linnaeus

Answer 38

Keep Ponds Cleans Or Fish Get Sick

Question 39

how did linnaeus classify living things

Answer 39

kingdom, phylum, class, order, family, genus and species

Question 40

variation may be due to difference in...

Answer 40

- the genes that have been inherited (nature) - the conditions in which they have developed (nurture) - combination (holistic)

Question 41

how have organisms been named

Answer 41

by binomial system of genus and species

Question 42

advantages of sexual reproduction

Answer 42

- produces variation in the offspring - if the environment changes, variation gives a survival advantage - natural selection can be increased

Question 43

advantages of asexual reproduction

Answer 43

- only one parent needed - more time and energy efficient as they do not need to find a mate - faster

Question 44

how can plants be cloned

Answer 44

- tissue culture - cuttings

Question 45

tissue culture method

Answer 45

- take out cells from a leaf - place into petri dish - place in correct conditions - many sapling will grow

Question 46

cuttings method

Answer 46

- propagation

Question 47

what does the dna structure contains

Answer 47

- nucleotide - phosphate - sugar - base - double helix