Genetics: Quiz 1

Question 1

Define genetics

Answer 1

Study of hereditary and variation of inherited characteristics

Question 2

Define DNA

Answer 2

stores hereditary info in organisms

Question 3

Define Chromatin

Answer 3

Term used to describe genetic material during interphase. Long stretched out strand of DNA in nucleus with all its proteins

Question 4

Define Gene

Answer 4

Segment of DNA that encodes for a specific piece of information/trait

Question 5

Define Diploid cell

Answer 5

Cells that have 2 copies of each chromosome

Question 6

Define haploid cell

Answer 6

Cells that have half the number of chromosomes

Question 7

Define homologous chromosomes

Answer 7

Chromosomes that code for the same info and are the same size. Not genetically identical.

Question 8

Define chromatid

Answer 8

A single “arm” in a duplicated chromosome

Question 9

Define sister chromatid

Answer 9

The 2 chromatids it a duplicated chromosome that are attached together at their centromere. Genetically identical.

Question 10

Explain Interphase

Answer 10

Period between cell divisions where cell undergoes normal activities (obtaining energy products, synthesizing, repairing damage)

G1 - (gap 1) cell does normal cell things and preps for S phase
S - (synthesis phase) DNA is replicated for cell division
G2 - (gap 2) cell begins final prep for cell division

Question 11

Explain mitosis

Answer 11

Cell division

Prophase- chromatins condense, nuclear membrane dissolves

Metaphase- spindle fibres guise chromosomes into middle of cell

Anaphase- spindle fibres pull sisters apart and pull cell to make cell bigger

Telophase- chromosomes uncoil, fibres dissolve, nuclear membrane forms.

Question 12

Why do some cells undergo division faster?

Answer 12

• different stages of life (childhood)
• cancer cells
• genetics
• some cells have shorter lives and need to reproduce faster

Question 13

Define meiosis

Answer 13

Division of the nucleus in sex cells.

Question 14

What is a tetrad?

Answer 14

A pair of homologous chromosomes, each with 2 sister chromatids

Question 15

What is crossing over?

Answer 15

The exchange of chromosome segments between homologous pairs during SYNAPSIS (physical pairing of homologous genes during prophase 1)

Question 16

What is synapsis?

Answer 16

Physical pairing of homologous chromosomes in prophase 1

Question 17

What is independent assortment?

Answer 17

Random distribution of a chromosome to a daughter cell depending on how chromosome alone up in metaphase 1 and 2

Question 18

Meiosis occours in this type of cell

Answer 18

Gametes

Question 19

Mitosis occurs in this type of cell

Answer 19

Somatic

Question 20

What is non disjunction?

Answer 20

The failure of homologous chromosomes to move to opposite poles of the cell during meiosis; results in an abnormal number of chromosomes in daughter cells

Question 21

What types of non disjunction are there?

Answer 21

TRISOMY - The gain of 1 extra chromosome (3 in place of 1 homologous pair)

MONOSOMY - the loss of 1 chromosome (one 1 copy where there should be a homologous pair)

Question 22

What is trisomy?

Answer 22

The gain of 1 extra chromosome (3 in place of 1 homologous pair)

Question 23

What is monosomy?

Answer 23

the loss of 1 chromosome (one 1 copy where there should be a homologous pair)

Question 24

Explain chromosomal errors

Answer 24

Deletions - sections of DNA are missing

Duplications - sections of DNA are duplicated

Inversions - sections of DNA are copied in reverse order

Translocations - sections of DNA are reattached to the wrong chromosome (non-homologous)

Question 25

What is a karyotype?

Answer 25

Photographic inventory of an individuals chromosomes, usually taken in late prophase or metaphase

Question 26

Define allele

Answer 26

Each genes possible different forms. Ex. Gene is hair colour and allele could be red, blonde or brown

Question 27

What are the 2 types of alleles?

Answer 27

Dominant (capitol letter) - always represented in physical characteristics of present Recessive (lower case) - only represented if there do dominant allele

Question 28

Define homozygous

Answer 28

An individual in which both alleles are the same. Homozygous dominant - BB Homozygous recessive - bb

Question 29

Define heterozygous

Answer 29

Hybrid An individual in which both alleles are different. Heterozygous - Bb

Question 30

Define genotype

Answer 30

Genetic make-up of the individual (BB/Bb/bb)

Question 31

Define Phenotype

Answer 31

Physical appearance of the individual

Question 32

Define Down Syndrome

Answer 32

- trisomy of 21 | - developmental and intellectual disabilities

Question 33

Define Turner Syndrome

Answer 33

- 1X/missing X | - don’t reach sexual maturity

Question 34

Define Klinefelter Syndrome

Answer 34

- 2X, 1Y | - exhibit some female body characteristics

Question 35

Define Patau Syndrome

Answer 35

- trisomy of 13 - major developmental issues - often only live a few months

Question 36

Define Edwards Syndrome

Answer 36

- trisomy of 18 - most fetuses die before birth - many organ systems defective