3 - Cell Division and Genetics REVIEW

Question 1

What is a chromosome made of?

Answer 1

DNA tightly coiled around proteins called histones.

Question 2

What is a chromatid?

Answer 2

One of two identical halves of a replicated chromosome.

Question 3

What holds sister chromatids together?

Answer 3

The centromere.

Question 4

What is the difference between a diploid and haploid cell?

Answer 4

Diploid (2n) has two sets of chromosomes; haploid (n) has one set.

Question 5

What are the stages of the cell cycle?

Answer 5

Interphase (G1, S, G2), Mitosis, Cytokinesis.

Question 6

What happens during the S phase?

Answer 6

DNA is replicated.

Question 7

What is the purpose of mitosis?

Answer 7

To create 2 identical diploid cells for growth and repair.

Question 8

What is the purpose of meiosis?

Answer 8

To produce 4 genetically unique haploid gametes.

Question 9

In what stage does crossing over occur?

Answer 9

Prophase I of meiosis.

Question 10

What causes Down syndrome?

Answer 10

Nondisjunction during meiosis (an extra chromosome 21).

Question 11

What is Turner Syndrome and what causes it?

Answer 11

Turner Syndrome is a genetic disorder in females caused by a missing or incomplete X chromosome. Instead of having two sex chromosomes (XX), a person with Turner Syndrome usually has only one X chromosome (45,X).

Question 12

What is Klinefelter Syndrome and what causes it?

Answer 12

Klinefelter Syndrome is a genetic disorder in males caused by an extra X chromosome. Instead of having the typical male chromosomes (XY), they have XXY (47,XXY). This can lead to lower testosterone, reduced fertility, and sometimes learning difficulties.

Question 13

What is Jacob’s Syndrome and what causes it?

Answer 13

Jacob’s Syndrome is a genetic condition in males caused by having an extra Y chromosome — so instead of XY, they have XYY (47,XYY). It usually doesn’t cause major symptoms, but some may be taller than average, have mild learning difficulties, or speech delays.

Question 14

What is a genotype?

Answer 14

The genetic makeup (e.g., Aa, BB).

Question 15

What is a phenotype?

Answer 15

The physical trait expressed (e.g., brown eyes).

Question 16

What is the difference between dominant and recessive?

Answer 16

Dominant alleles mask recessive ones in heterozygotes.

Question 17

What is a Punnett square used for?

Answer 17

To predict the probability of offspring genotypes and phenotypes.

Question 18

What is a pedigree chart?

Answer 18

A family tree that shows inheritance of a trait.

Question 19

What is the shape of DNA?

Answer 19

A double helix.

Question 20

What are the base-pair rules?

Answer 20

A pairs with T, C pairs with G.

Question 21

What is the backbone of DNA made of?

Answer 21

Sugar (deoxyribose) and phosphate.

Question 22

What is transcription?

Answer 22

Making mRNA from DNA in the nucleus.

Question 23

What is translation?

Answer 23

Ribosomes use mRNA to assemble amino acids into a protein.

Question 24

What is a codon?

Answer 24

A 3-base mRNA sequence that codes for an amino acid.

Question 25

What is a mutation?

Answer 25

A change in the DNA sequence, which can alter proteins.

Question 26

What is the correct order of events in mitosis?

Answer 26

Prophase → Metaphase → Anaphase → Telophase (PMAT)

Question 27

n what stage of mitosis do chromosomes line up at the equator?

Answer 27

Metaphase

Question 28

What happens during anaphase?

Answer 28

Sister chromatids are pulled apart to opposite poles.

Question 29

What causes Turner Syndrome?

Answer 29

ondisjunction during meiosis resulting in only one X chromosome (XO).

Question 30

What phase does chemotherapy that targets DNA replication affect?

Answer 30

Interphase (specifically S phase).

Question 31

What’s the chromosome number of a human somatic cell?

Answer 31

2n = 46.

Question 32

What is the result of meiosis?

Answer 32

Four non-identical haploid gametes (n = 23 in humans).

Question 33

What does crossing over in Prophase I do?

Answer 33

Increases genetic variation.

Question 34

What is parthenogenesis?

Answer 34

Asexual reproduction where an unfertilized egg develops into an organism.

Question 35

What’s the chance a son will inherit an X-linked disorder from a carrier mom?

Answer 35

50%

Question 36

In incomplete dominance, what happens in heterozygotes?

Answer 36

A blend of traits (e.g., red x white = pink flowers)

Question 37

What does codominance mean?

Answer 37

Both alleles show up fully (e.g., AB blood type).

Question 38

What enzyme is used to cut genes for genetic engineering?

Answer 38

Restriction enzyme.

Question 39

What enzyme is used to paste genes into plasmids?

Answer 39

DNA ligase.

Question 40

What type of RNA carries the message from DNA to the ribosome?

Answer 40

mRNA.

Question 41

What is the anticodon for the mRNA codon AUG?

Answer 41

UAC.

Question 42

What happens during transcription?

Answer 42

DNA is used as a template to make mRNA.

Question 43

What happens during translation?

Answer 43

mRNA is used to assemble amino acids into a protein at the ribosome.