B6 The Rest I Need To Know

Question 1

What is a Genetic Family Tree?

Answer 1

A family tree (also called a pedigree chart) shows how a genetic condition is inherited through generations.

Question 2

Gene

Answer 2

A section of DNA that controls a trait

Question 3

Allele

Answer 3

A version of a gene (e.g. A or a)

Question 4

Genotype

Answer 4

The combination of alleles (e.g. Aa)

Question 5

Phenotype

Answer 5

The physical trait (e.g. brown eyes)

Question 6

Recessive

Answer 6

2 copies needed to show the trait (e.g. aa)

Question 7

Dominant

Answer 7

Only 1 copy needed to show the trait (e.g. A)

Question 8

Carrier

Answer 8

Has 1 recessive allele but doesn’t show the trait (e.g. Aa

Question 9

Example: Inheriting a Recessive Disorder

Answer 9

• A = healthy allele (dominant)
• a = faulty allele (recessive)

Question 10

If two healthy parents have an affected child

Answer 10

→ the condition is recessive

Question 12

Key Genetic Terms:

Answer 12

Question 14

• If one parent has the condition and passes it to half the children

Answer 14

→ likely dominant

Question 15

Carriers =

Answer 15

heterozygous (Aa)
✅ Recessive traits can skip generations

Question 16

Dominant

Answer 16

only needs one allele to show up

Question 17

What is Embryo Screening?

Answer 17

Embryo screening checks if an embryo has genetic disorders before it’s used in IVF (in vitro fertilisation).

Question 18

How It Works

Answer 18

1. Embryos are made by IVF
   
   2. A cell is removed from each embryo
   3. The DNA is tested for genetic conditions
   4. Embryos without the disorder are selected
   5. Only healthy embryos are implanted into the womb

Question 19

Advantages of Embryo Screening

Answer 19

• Helps parents avoid passing on genetic disorders
• Reduces suffering
• Can save money on future treatment

Question 20

Disadvantages / Ethical Issues of embryo screening

Answer 20

• May be seen as unethical (choosing embryos = “designer babies”)
• Could lead to discrimination
• Some embryos are destroyed
• May be expensive

Question 21

Only used in IVF is …

Answer 21

not natural pregnancy

Question 22

Not all embryos are…

Answer 22

implanted — some are destroyed

Question 23

Screening can cause

Answer 23

ethical concerns

Question 25

What does a family tree show?

Answer 25

How a genetic condition is passed through generations.

Question 26

What is a dominant allele?

Answer 26

An allele that shows its effect even if only one is present.

Question 27

What is a recessive allele?

Answer 27

An allele that only shows its effect if two copies are present.

Question 28

What is a carrier?

Answer 28

Someone who has one recessive allele but does not have the disorder.

Question 29

What is embryo screening?

Answer 29

Testing embryos for genetic disorders during IVF.

Question 30

Why do some people support embryo screening?

Answer 30

It can prevent suffering from inherited diseases

Question 31

Why are some people against embryo screening?

Answer 31

It may be unethical and involve destroying embryos.

Question 32

What type of inheritance can skip generations?

Answer 32

Recessive inheritance

Question 33

What is Variation?

Answer 33

Variation means differences between individuals of the same species. For example: hair colour, height, eye colour, blood type.

Question 34

Causes of Variation

Answer 34

✅ 1. Genetic Variation • Caused by differences in genes inherited from parents • Happens through sexual reproduction (meiosis) • Leads to genetic differences in offspring

Question 35

Example of causes of variation Genetic Variation

Answer 35

Examples: • Eye colour • Blood group • Natural hair colour • Genetic disorders

Question 36

2. Environmental Variation

Answer 36

• Caused by surroundings/lifestyle, not genes • Examples: • Scars • Language spoken • Tattoos/piercings • Diet (e.g. muscle growth, weight gain)

Question 37

Example of causes of variation Genetic Variation

Answer 37

Examples: • Eye colour • Blood group • Natural hair colour • Genetic disorders

Question 38

✅ 3. Both Genes and Environment

Answer 38

Some characteristics are affected by both genetics and the environment • Examples: • Height (genes decide potential, diet affects actual height) • Weight (genetics + lifestyle) • Intelligence (some genetic influence + education and environment)

Question 39

All the Causes of Variation

Answer 39

✅ 1. Genetic Variation ✅ 2. Environmental Variation ✅ 3. Both Genes and Environment

Question 40

Where Does Genetic Variation Come From?

Answer 40

🔁 Sexual Reproduction • Causes variation by mixing of genes from both parents • Each child gets a unique combination of alleles

Question 41

Mutation

Answer 41

• A mutation is a random change in DNA • Can introduce new variation • Most mutations have no effect or are harmful • Rarely, a mutation is beneficial and gives an advantage (e.g. resistance to disease)

Question 42

Why is Variation Important?

Answer 42

• Variation is essential for natural selection • It allows species to adapt to changes in the environment • Without variation, all organisms would be the same — if one dies from disease, they all might

Question 43

Variation can be…

Answer 43

genetic, environmental or both

Question 44

Sexual reproduction

Answer 44

increases variation

Question 45

Asexual reproduction = clones variation or not

Answer 45

Asexual reproduction = no variation (clones)

Question 46

Mutations create new alleles, which can cause

Answer 46

variation

Question 47

Height and weight are affected by

Answer 47

both genes and environment

Question 48

Most mutations are…

Answer 48

neutral or harmful, not helpful

Question 49

Clones have no variation, unless

Answer 49

a mutation happens

Question 50

What is variation?

Answer 50

The differences between individuals of the same species.

Question 51

What causes genetic variation?

Answer 51

Differences in genes inherited from parents

Question 52

What causes environmental variation?

Answer 52

Differences in lifestyle or surroundings.

Question 53

Give one characteristic caused by both genes and the environment

Answer 53

Height or weight

Question 54

What is a mutation?

Answer 54

A random change in DNA

Question 55

Do most mutations help or harm an organism?

Answer 55

Most have no effect or are harmful.

Question 56

What type of reproduction causes variation?

Answer 56

Sexual reproduction

Question 57

Why is variation important for survival?

Answer 57

It allows species to adapt to environmental changes.