Genetics

Question 1

What is genetics?

Answer 1

Genetics is the field of biology that involves the study of heredity and variation of living organisms and how genetic information is passed from one generation to the next.

Question 2

What does the cell theory state?

Answer 2

• all living things are composed of one of more cells
• cells are the smallest units of living organisms
• new cells come only from pre-existing cells

Question 3

What is the first stage of the cell cycle? What happens?

Answer 3

Interphase

-cell carries out normal functions, grows, makes copies of its genetic material to prepare for mitosis

Question 4

What is the second stage of the cell cycle? What happens

Answer 4

Mitosis: cell nucleus and genetic material divides

PMAT

Question 5

What happens during prophase?

Answer 5

-cell’s chromatin condenses into chromosomes

Question 6

What happens during metaphase?

Answer 6

-spindle fibres from opposite poles attach to the centromere of each chromosome, guiding the chromosomes to the equator of the cell

Question 7

What happens during anaphase?

Answer 7

-each centromere splits apart and the sister chromatids separate from each other

Question 8

What happens during telophase?

Answer 8

• the chromosomes start to unwind into strands of chromatin
• the spindle fibres break down
• the nuclear membrane forms around the new set of chromosomes and a nucleolus forms within each new nucleus

Question 9

What happens during cytokinesis?

Answer 9

-divison of cell cytoplasm and creation of new cell

Question 10

What is DNA?

Answer 10

• stands deoxyribonucleic acid and DNA is how traits are passed onto new cells (genetic makeup)
• Adenine, guanine, thymine, cytosine

Question 11

What is a nucleotide?

Answer 11

-the individual units of each strand of DNA

Phosphate, sugar and base (Adenine-Thymine, Guanine-Cytosine)

Question 12

What is mitosis?

Answer 12

-stage where cell division occurs to create a new cell

Question 13

What is meiosis?

Answer 13

-the process of cell division that produces haploid cells

Question 14

What are the differences between mitosis and meiosis?

Answer 14

Mitosis

• 2 identical daughter cells
• daughter cells are identical to parent cells
• 4 phases
• crossing over does not occur
• chromosome pairs line up
• somatic (body) cells produced

Meiosis

• female: 1 egg and 3 polar bodies
  male: 4 sperm
• daughter cells are not identical to parent cells
• 8 phases
• crossing over can occur
• chromosome pairs line up
• sex cells produced

Question 15

What is independent assortment?

Answer 15

• happens in metaphase 1

- how the chromosomes line up is what decides the variation in diploid offspring of the haploid cells

Question 16

What is crossing over?

Answer 16

• happens during synapsis of prophase 1

- the exchange of chromosomal segments between a pair of homologous chromosomes

Question 17

What is recombination?

Answer 17

-recombining the maternal and paternal chromosomes so that new forms are created (this is variation in the creation of gametes)

Question 18

What is deletion?

Answer 18

-when a piece of chromosome is deleted

Question 19

What is duplication?

Answer 19

-when a section of chromosome appears two or more times in a row

Question 20

What is inversion?

Answer 20

-when a section of a chromosome is inverted

Question 21

What is translocation?

Answer 21

-when a segment of one chromosome becomes attached to a different chromosome

Question 22

What is the law of segregation?

Answer 22

-traits are determined by pairs of alleles that segregate during meiosis so that each gamete receives one allele

Question 23

What is a dominant allele?

Answer 23

-always appears when an individual has an allele for it

Question 24

What is a recessive allele?

Answer 24

-only appears when an individual has two alleles for it

Question 25

What is a genotype?

Answer 25

-the combination of alleles for any given trait or an organism’s entire genetic makeup

Question 26

What is a phenotype?

Answer 26

The physical and physiological traits of an organism

Question 27

What would you need to cross to get a 3:1 ratio?

Answer 27

HH x hh (homozygous dominant with heterzygous)

Question 28

What would you need to cross to get a 9:3:3:1 ratio?

Answer 28

HhMm x HhMm

Question 29

Homozygous dominant vs homozygous recessive?

Answer 29

HH and hh

Question 30

What is the difference between mono hybrid and dihybrid?

Answer 30

Monohybrid: homozygous/heterozygous dominant or homozygous recessive
Dihybrid: same as monohybrid but with 2 traits

Question 31

What is the law of independent assortment?

Answer 31

-during gamete formation, the two alleles for one gene segregate or assort independently of the alleles for the other genes.
This means that there are many different variations of an offspring because the genes mix and match.

Question 32

What is autosomal inheritance?

Answer 32

-the inheritance of traits determined by genes on the autosomal chromosomes (1-22 in humans)

Question 33

What is autosomal dominant?

Answer 33

-the inheritance of a dominant phenotype whose gene is on an autosomal chromosome (1 copy of allele is needed)

Question 34

What is autosomal recessive?

Answer 34

-the inheritance of recessive phenotype whose gene is on an autosomal chromosome (must have 2 copies of allele)

Question 35

What is incomplete dominance?

Answer 35

Neither of the two alleles for a gene can completely conceal each other (red + white flower = pink flower)

Question 36

What is co dominance?

Answer 36

Both alleles are fully expressed (red roan horses)