You and your genes

Question 1

What carries the instructions for the proteins that are needed to make your cells to work?

Answer 1

Genes

Question 2

What chemical makes up a gene?

Answer 2

DNA (DeoxyriboNucleic Acid)

Question 3

What are the coils of DNA called?

Answer 3

Chromosones

Question 4

What is the shape of a chromosome?

Answer 4

Double helix

Question 5

How do you tell the sex of a chromosome?

Answer 5

Take off its genes. In mammals, the y chromosome makes male, XX is female.

Question 6

Where would you find the chromosomes?

Answer 6

In the cell nucleus

Question 7

How are genes coded?

Answer 7

The order of the bases determines the order of the amino acids in the protein

Question 8

What two groups of proteins are coded on genes?

Answer 8

Functional proteins and structural proteins.

Question 9

What is a functional protein?

Answer 9

A protein needed to make the body function, eg enzymes, hormones, antibodies

Question 10

What is a structural protein?

Answer 10

A protein that is part of the structure of the body, eg skin (keratin) or collagen (found in skin, ligaments)

Question 11

What was the project to map the human genes called?

Answer 11

The human genome project

Question 12

What is the complete set of genes of an organism called?

Answer 12

The genome

Question 13

What controls the characteristics of an organism?

Answer 13

Genes, environment, or a combination.

Question 14

What are the ethical considerations of the human genome project?

Answer 14

Some companies want to patent genes. They would then “own” genes and could charge other scientists to investigate those genes. This would restrict research.

Question 15

What is the consequences of differences in genes?

Answer 15

Variations within the species.

Question 16

How many genes control each characteristic?

Answer 16

It can be one, or many.

Question 17

If there are many genes controlling a characteristic how is the characteristic expressed within the population?

Answer 17

There will be continuous variation within the population, eg height.

Question 18

What is the genotype?

Answer 18

The genes of an organism, usually expressed as two letters, eg Ee

Question 19

What is the phenotype?

Answer 19

The observable physical characteristic of the organism

Question 20

What is the phenotype affected by?

Answer 20

Genes and environment.

Question 21

Why are studies on identical twins so valuable?

Answer 21

It enables research into the effects of the environment on an organism.

Question 22

How many pairs of chromosomes does the human have?

Answer 22

23

Question 23

How many chromosomes does the human have?

Answer 23

46

Question 24

How many chromosomes in a human sex cell?

Answer 24

23

Question 25

What do a sperm cell and an egg form when they combine?

Answer 25

A zygote

Question 26

What is the process of the joining of egg and sperm?

Answer 26

fertilisation

Question 27

How many chromosomes in the human zygote?

Answer 27

46

Question 28

What are changes to DNA called?

Answer 28

Mutation

Question 29

Why do brothers and sisters vary when they have the same parents?

Answer 29

It is random which chromosome they inherit from each parent, so the chance of getting the same mixture is 1 in 2 to the power of 46

Question 30

What is an allele?

Answer 30

The different forms in which a gene controlling a characteristic can occur,

Question 31

If an organism has the same allele on each chromosome for a particular characteristic this is called .....

Answer 31

Homozygous

Question 32

If an organism has different alleles on each chromosome for a particular characteristic this is called ....

Answer 32

Heterozygous

Question 33

If an allele is expressed when there are two different alleles present this is called...

Answer 33

Dominant

Question 34

Dominant alleles are written as ..... in genetic diagrams

Answer 34

A single capital letter

Question 35

Recessive alleles are written as ... in genetic diagrams

Answer 35

A single lower case letter

Question 36

For the recessive trait to show there must be at least .... recessive alleles present

Answer 36

Two

Question 37

For the dominant trait to show there must be at least .... dominant allele present

Answer 37

One

Question 38

What does a Punnett square enable you to show?

Answer 38

The probability of two parents producing different types of offspring

Question 39

How is human sex (normally) determined?

Answer 39

By chromosome 23

Question 40

What is the female chromosome shown as in genetic diagrams?

Answer 40

XX

Question 41

What is the male chromosome shown as in genetic diagrams?

Answer 41

XY

Question 42

What causes a sex-linked disorder?

Answer 42

The y chromosome is shorter. If a defective gene is found on the part of the X chromosome that has no matching allele on the Y chromosome then that gene must be expressed in boys, even if it is recessive.

Question 43

What determines the sex of a baby?

Answer 43

The presence of the Y chromosome, without it the baby will be female.

Question 44

Name a genetic disorder that is dominant

Answer 44

Huntington's

Question 45

Name a genetic disorder that is recessive

Answer 45

cystic fibrosis

Question 46

What is a carrier of a genetic disorder?

Answer 46

A person that has one copy of the defective gene that can be passed to offspring but they do not show the disorder.

Question 47

What is screening for genetic disorders?

Answer 47

It is when the whole population is tested even if there is no history in the family, eg the heel prick test on babies.

Question 48

What is genetic testing?

Answer 48

The testing of an individual for a genetic gene, usually done when there are reasons to believe there is a problem, eg family history, or abnormal development in a baby.

Question 49

What ethical questions are raised by genetic testing?

Answer 49

One big one is the question whether the person has to disclose he information to, for instance, an employer, or an insurance company, and whether the information can be used to make decisions about whether to employ/insure.

Question 50

How is genetic testing in pregnancy done?

Answer 50

Amniocentesis or chorionic villus sampling

Question 51

What is amniocentesis?

Answer 51

Collecting fetal cells from the amniotic fluid by using a needle through the mum's abdomen

Question 52

What is chorionic villus sampling

Answer 52

Testing a sample of fetal cells from the placenta (usually via the vagina).

Question 53

What is the risk of miscarriage due to genetic testing?

Answer 53

About 1%

Question 54

What is embryo screening?

Answer 54

Checking embryos produced by IVF prior to implantation

Question 55

What is the process of screening embryos for genetic defects called?

Answer 55

Pre-implantation genetic diagnosis (PGD)

Question 56

Is there any control over the production of human embryos?

Answer 56

In the UK there are strict guidelines.

Question 57

What choices to parents with a genetic abnormality face?

Answer 57

They may decide not to have children, or they may face the choice of terminating a pregnancy

Question 58

Are genetic tests 100% reliable?

Answer 58

No, both false positives and false negatives occur

Question 59

What are clones?

Answer 59

Genetically identically individuals

Question 60

If an organism clones itself, what is this called?

Answer 60

Asexual reproduction

Question 61

Can human beings have clones?

Answer 61

Yes, identical twins are clones

Question 62

What are the advantages of asexual reproduction?

Answer 62

All the offspring have the successful genes; a single animal can colonise a new area

Question 63

What are the disadvantages of asexual reproduction?

Answer 63

Lack of variation means that any challenge to the species could wipe it out - eg climate change/disease.

Question 64

Can mammals be cloned?

Answer 64

Yes

Question 65

Is is legal to clone human beings?

Answer 65

Not in the UK

Question 66

How was Dolly cloned?

Answer 66

A nucleus from one of her body cells was extracted and injected into an egg cell that had already had its nucleus removed. This zygote is stimulated to start dividing and the resultant embryo is implanted into a surrogate mother.

Question 67

What is the process of a cell becoming specialised called?

Answer 67

Differentiation

Question 68

What are the unspecialised cells in the embryo called?

Answer 68

Embryonic stem cells

Question 69

What are adult stem cells?

Answer 69

Cells that can develop into a limited range of different cell types, eg bone marrow stem cells to blood cells

Question 70

Why is the use of embryonic stem cells controversial?

Answer 70

They come from unused embryos from fertility treatments,, and the embryo is destroyed.

Question 71

What are the uses of stem cells?

Answer 71

Testing new drugs; understanding the specialising of cells by the switching on/off genes; renewing damaged cells in the spine/heart