Topic 6

Question 1

What is a haploid?

Answer 1

Have a single set of unpaired chromosomes (23)

Ex: sex cells

Question 2

What is a diploid?

Answer 2

Have two complete sets of chromosomes (46)

Ex: normal body cells

Question 3

What are autosomal chromosomes?

Answer 3

The numbered chromosomes excluding the sex chromosomes (22 pairs)

Genetic code for the same trait is at the same spot for a chromosome pair, or autosomes

Question 4

Define phenotype.

Answer 4

The observable physical traits of an organism

Ex: purple, purple, white

Question 5

What is the relationship between genotype and phenotype?

Answer 5

Phenotype is the physical manifestation of the genotype

Environmental factors can change how genotype is expressed, leading to variations within a phenotype

Question 6

Define genotype.

Answer 6

The genetic makeup of an organism

Ex: homozygous dominant (BB), heterozygous (Bb), homozygous recessive (bb)

Question 7

What can affect the expression of genotype?

Answer 7

Environmental factors

These can lead to variations within a phenotype

Question 8

What is a gene?

Answer 8

Genetic information for a particular trait

Question 9

Define allele.

Answer 9

When genes are present in multiple forms on autosomal chromosomes

Question 10

What does variation refer to?

Answer 10

Difference between individuals of the same species

May be due to DNA inherited from parents, exposure to certain environmental factors, or a combination of both

Question 11

What are the types of variation?

Answer 11

Can be helpful, harmful, or neutral

Question 12

What is a mutation?

Answer 12

Any change in the DNA of a gene or chromosome

Can cause an organism’s trait to be different from what it normally would be

Question 13

What is the result of mitosis?

Answer 13

Two identical diploid daughter cells

Mitosis produces regular body cells.

Question 14

What are the three stages of interphase in mitosis?

Answer 14

Growth 1, Synthesis, Growth 2

Interphase involves cell growth and DNA replication.

Question 15

What occurs during prophase of mitosis?

Answer 15

Nuclear membrane disappears, chromatin condenses to form chromatids, centrioles move to opposite ends

Spindle fibers are also formed in this stage.

Question 16

What happens during metaphase of mitosis?

Answer 16

Sister chromatids line up in the center, spindle fibers attach

This stage prepares chromatids for separation.

Question 17

What is the key event in anaphase of mitosis?

Answer 17

Centromere splits, sister chromatids are pulled apart

This results in the formation of individual chromosomes.

Question 18

What occurs during telophase of mitosis?

Answer 18

Nuclear membrane reappears, chromosomes unravel to become chromatin

Telophase is essentially the reverse of prophase.

Question 19

What is cytokinesis?

Answer 19

Cell ‘pinches’ down in the middle, cytoplasm splits into two identical daughter cells

This completes the cell division process.

Question 20

What is the result of meiosis?

Answer 20

Four non-identical haploid daughter cells

Meiosis produces sex cells or gametes.

Question 21

What is synapsis in meiosis?

Answer 21

The coming together of homologous pairs to form a tetrad

This occurs during prophase I.

Question 22

What is crossing over in meiosis?

Answer 22

tetrads exchange some genes to ensure variety

This process creates recombinant chromosomes.

Question 23

What are inherited mutations?

Answer 23

Mutations passed from parent to offspring during reproduction

These are present in every cell of the offspring’s body.

Question 24

What are acquired mutations?

Answer 24

Mutations that occur at some point during an organism’s life

They can only be passed on if they occur in sex cells.

Question 25

What are genetic mutations?

Answer 25

Result of small changes in an organism's DNA ## Footnote They may cause incorrect proteins to be made.

Question 26

What are sex-linked mutations?

Answer 26

Mutations occurring on genes carried on a sex chromosome ## Footnote Most sex-linked mutations are on the X chromosome.

Question 27

What can cause mutations during reproduction?

Answer 27

Chromosomes do not separate correctly during meiosis ## Footnote This can lead to sex cells with too many or too few chromosomes.

Question 28

What are 'jumping genes'?

Answer 28

Genes that move to a new location on the genome ## Footnote Their movement can disrupt functioning genes and cause mutations.

Question 29

Provide an example of a helpful mutation.

Answer 29

Mutation in a gene controlling fast-twitch muscles ## Footnote This can produce world-class sprinters.

Question 30

Provide an example of a harmful mutation.

Answer 30

Cystic fibrosis ## Footnote This genetic disorder causes thick mucus in the lungs and digestive system.

Question 31

What are mutagens?

Answer 31

Harmful chemicals and radiation that can damage DNA ## Footnote They can be natural (like UV radiation) or synthetic (like pesticides).