B5.1 - Genes, Inheritence And Selection

Question 1

What is variation?

Answer 1

Differences within a species. There are two types: genetic and environmental

Question 2

What is environmental variation? Give some examples

Answer 2

Variation affected by the environment in which you live. Some examples are :

• hair colour
• Language
• Skill
• Number of fruit produced by a plant

Question 3

What is genetic variation?

Answer 3

Variation affected by the genes you inherit from your parents. Examples:

• Skin colour
• Blood group
• Eye colour

Question 4

What is a phenotype

Answer 4

Phenotype is the appearance or characteristics of an organism, eg face

Question 5

Name some characteristics affected by both

Answer 5

Height- depends on your parents and diet

Question 6

What is genotype?

Answer 6

The set of genes responsible for a certain characteristic

Question 7

What is discontinuous and continuous variation?

Answer 7

Dis- characteristics fall into distinct groups, eg blood group. Controlled by multiple genes and is caused by genetic and environmental

Con- a characteristic between certain values, such as height. Caused by genetic variation and controlled by a few genes

Question 8

What is a clone?

Answer 8

An organism that is genetically identical to its parent

Question 9

What is asexual reproduction?

Answer 9

Asexual reproduction is when offspring is produced by mitosis from only one parent. The genetic material is replicated and the cells divide through mitosis. The genes are identical therefore the offspring is a clone.

Question 10

What is sexual reproduction?

Answer 10

Sexual reproduction requires 2 parents. Genetic material is taken from both parents so the offspring is not a clone as variation occurs. The sex cells are called gametes and they fuse together to form a full diploid to form a zygote

Question 11

Asexual advantages and disadvantages

Answer 11

Advantages:

• the parent will pass on the beneficial characteristics to the next generation
• only one parent is needed which means that reproduction occurs faster

Disadvantage
-changes to the environment can destroy a species if it is not well adapted because variation does not occur

Question 12

Sexual advantages and disadvantages

Answer 12

Advantages:
-Variation leads to adaptations within a species. Organisms can cope with environmental pressure and the species can evolve through natural selection

Disadvantage

• Requires 2 parents, so it is slower
• need to find mates

Question 13

What is meiosis?

Answer 13

Meiosis is a type of cell division which does not produce identical cells. It happens during sexual reproduction in humans to produce haploid gametes:sperm and egg.

Question 14

What are haploid and diploids?

Answer 14

Haploid are sex cells with 23 chromosomes in humans. Diploids are normal body cells with 46 chromosomes.
Zygotes are diploid cells formed when 2 haploid gametes join together. It divides using mitosis to produce an embryo

Question 15

Describe the process of meiosis

Answer 15

1)

Question 16

What does genome mean?

Answer 16

The entire genetic makeup of an organism. All sexually reproduced offspring have individual genomes