B5.1: Inheritance

Question 1

What is a phenotype?

Answer 1

The appearance of an organism

Question 2

What is variation?

Answer 2

Differences within a species

Question 3

What are the 2 causes of variation?

Answer 3

Environmental variation
Genetic variation

Question 4

What is genetic variation?

Answer 4

Genetic material inherited from parents

Question 5

What is environmental variation?

Answer 5

The environment in which you live in

Question 6

What is an example of a characteristic that is affected both by environmental and genetic variation?

Answer 6

Height - if your parents are tall you are more likely to be tall BUT if your diet is very poor you may not grow to your full potential height

Question 7

What are examples of characteristics caused by genetic variation alone?

Answer 7

Eye colour
Blood group

Question 8

What is discontinuous variation?

Answer 8

Can only result in specific values that fall into distinct groups.

Question 9

How can discontinuous variation be represented?

Answer 9

Bar charts

Question 10

What is continuous variation?

Answer 10

Can take up any value within a range. A characteristic can be any value between a minimum and maximum.

Question 11

How can continuous variation be represented?

Answer 11

Histogram

Question 12

What are the causes of continuous variation?

Answer 12

Genetic and environmental

Question 13

What are the causes of discontinuous variation?

Answer 13

Genetic

Question 14

What are examples of continuous variation?

Answer 14

Height
Weight

Question 15

What are examples of discontinuous variation?

Answer 15

Gender
Eye colour

Question 16

How many genes are continuous variation controlled by?

Answer 16

Multiple genes

Question 17

How many genes are discontinuous variation controlled by?

Answer 17

One (or few) gene(s)

Question 18

What is asexual reproduction?

Answer 18

Creating a genetically identical copy of the parent, often ocurring through the process of mitosis

Question 19

Who performs asexual reproduction?

Answer 19

Bacteria
Some plants
Some animals

Question 20

What are some examples of plants who reproduce asexually?

Answer 20

Potato plants
Daffodils

Question 21

What are advantages of asexual reproduction?

Answer 21

Faster reproduction
If parent is well adapted to the area, offspring will have the exact same genetic info

Question 22

What are disadvantages of asexual reproduction?

Answer 22

No genetic variation
Harmful mutation will pass onto offspring because it’s an exact clone

Question 23

What is sexual reproduction?

Answer 23

Requires 2 parents as genetic info is taken from both of them. Results in variation. Performed by meiosis

Question 24

What are advantages of sexual reproduction?

Answer 24

Genetic variation within the population
More likely that offspring will be able to survive from environmental changes: evolution —> species become better adapted

Question 25

What are disadvantages of sexual reproduction?

Answer 25

Takes more time/energy: fewer offspring 2 parents needed - problem if individuals are isolated

Question 26

What does sexual reproduction produce?

Answer 26

Sex cells: gametes Gametes fuse together in fertilisation. Egg develops into offspring

Question 27

What are diploid cells?

Answer 27

Two complete sets of each chromosome (46)

Question 28

What are haploid cells?

Answer 28

One set of chromosome (23)

Question 29

What is a zygote?

Answer 29

Fertilised egg where 2 haploid cells join together during fertilisation

Question 30

What is a genome?

Answer 30

The entire genetic material of an organism

Question 31

What is cell division?

Answer 31

Caused by meiosis Results in 4 haploid cells being produced from one diploid parent cell

Question 32

How many times does the nucleus split in meiosis?

Answer 32

2 times

Question 33

What are alleles?

Answer 33

Different forms of a gene

Question 34

What is a dominant allele?

Answer 34

A form of a gene that is fully expresed. Only one copy is needed for the characteristic to be expressed

Question 35

What is a recessive allele?

Answer 35

The gene that will not be expressed if in the presence of a dominant gene. Two recessive alleles are needed for the characteristic to be expressed

Question 36

Suppose B and b are the alleles for a recessive genetic condition. What will the homozygous dominant outcome be?

Answer 36

BB

Question 37

Suppose B and b are the alleles for a recessive genetic condition. What will the homozygous recessive outcome be?

Answer 37

bb

Question 38

Suppose B and b are the alleles for a recessive genetic condition. What will the heterozygous outcome be?

Answer 38

Bb

Question 39

What is homozygous?

Answer 39

An organism that has two identical alleles for a characteristic

Question 40

What is heterozygous?

Answer 40

An organism that has 2 different alleles for a characteristic

Question 41

What is a genotype?

Answer 41

The alleles present for a particular gene make up

Question 42

What is a gene?

Answer 42

A short section of DNA that contains instructions for a protein

Question 43

What are chromsomes?

Answer 43

These are made up of DNA and are found inside the nucleus. Each one contains a number of genes. Genetic info is carried on them

Question 44

What is the 23rd pair of chromosome?

Answer 44

Which pair of chromosomes determines the sex

Question 45

XY

Answer 45

Male sex chromosomes

Question 46

XX

Answer 46

Female sex chromosomes

Question 47

What are mutations?

Answer 47

Any change in the DNA base sequence

Question 48

What is a punnet square?

Answer 48

A chart that shows all the possible combinations of alleles that can result from a genetic cross

Question 49

What can increase chances of mutations?

Answer 49

Benzene Ethanol Ionising radiation

Question 50

What is a genetic variant?

Answer 50

Different version of the gene an allele

Question 51

How does mutations affect phenotype?

Answer 51

Most of the time, it doesn’t. But sometimes it does

Question 52

What are examples of mutations that affect phenotype?

Answer 52

Cystic fibrosis Sickle cell anaemia Huntingtons Albanism

Question 53

What is an example of a disease caused by mutations?

Answer 53

Cancer

Question 54

Why are a few mutations beneficial?

Answer 54

They cause resistance to antibiotics in bacteria cells This increasess bacteria survival chance, helpful for the bacteria

Question 55

What happens to DNA bases in a mutation?

Answer 55

Bases may be added, changed or deleted. The order of amino acids may be assembled differently, meaning the wrong protein is created If the protein is an enzyme, active site may be changed, meaning it can no longer bind to the substrate. This means certain metabolic reactions won’t be able to occur

Question 56

What did Gregor Mendel discover? When?

Answer 56

1866 Introduced the concept of hereditary

Question 57

What did Friedrich Miescher discover? When?

Answer 57

1869 Discovered DNA

Question 58

What did Oswald Avery discover? When?

Answer 58

1944 Genes are made of DNA

Question 59

What did Erwin Chargaff discover? When?

Answer 59

1950 DNA contains equal amounts of ACGT

Question 60

What did Wilkins and Franklin discover? When?

Answer 60

1952 Imaged DNA crystals using x-rays

Question 61

What did Aston and Crick discover? When?

Answer 61

1953 Published description of double helix

Question 62

What was discovered in 2003?

Answer 62

Scientists sequenced around 24,000 genes in the human genome

Question 63

What current research is going on? From when?

Answer 63

2003+ Cure genetic diseases

Question 64

How many genes are phenotypic features a result of?

Answer 64

Most phenotypic features are the result of multiple genes rather than single gene inheritance