intro to genetics

Question 1

genetics

Answer 1

• study of heredity and variation of inherited characteristics
• DNA is the information carrying molecule located in the nucleus of eukaryotic cells

Question 2

chromosome

Answer 2

• condensed, coiled up molecules of DNA that contain thousands of genes
• found in nucleus of eukaryotic cell

Question 3

gene

Answer 3

• segment of DNA molecule that encodes for a specific piece of information/trait (e.g. the gene for eye colour)
• occupies specific location (locus or loci) on a chromosome

Question 4

allele

Answer 4

• alternative forms of a gene located at the same place on a chromosome (e.g. blue vs brown eye colour)

Question 5

homologous chromosomes

Answer 5

• chromosomes that code for the same information
• pair of chromosomes carrying different alleles of the same gene (e.g. one homologous pair encodes for blue eyes, the other homologous pair encodes for brown eyes, but they both encode for eye colour)

Question 6

how many chromosomes in somatic cells

Answer 6

• 46
• 23 pairs of homologs (one from each parent)

Question 7

karyotype

Answer 7

profile of organism’s chromosomes to diagnose genetic disorders

Question 8

autosomes

Answer 8

• a chromosome that is not involved in determining the sex of an organism
• humans have 22 pairs

Question 9

sex chromosomes

Answer 9

• a chromosome that determines the sex of an organism
• humans have one pair
• males: XY
• female: XX

Question 10

diploid vs. haploid

Answer 10

• diploids have two copies of each chromosome (2n) e.g. somatic cells
• haploids have half the number of chromosomes (n) e.g. gametes

Question 11

advantages of asexual reproduction

Answer 11

• no finding mate
• no specialized mating behaviours
• no specialized anatomy
• heredity direct and invariable

Question 12

why do body cells divide?

Answer 12

• zygote into embryo
• organisms get bigger
• repair injuries
• replace old/dead cells

Question 13

advantages of sexual reproduction

Answer 13

variable offspring and traits to adapt to change
(fusion of 2 sex cells)

Question 14

two key processes in sexual reproduction

Answer 14

• meiosis: formation of haploid sex cells (gametes) which contain genetic information of parents
• fertilization of two sex cells to produce a zygote (first cell of new individual)

Question 15

meiosis

Answer 15

• type of cell division which produces gametes (sperm and egg)
• involves two divisions (I and II)
• reduces chromosome number from 46 to 23
• allows for genetic variation