Chapter 2: Genetics Flashcards
define variant
a particular form of a trait (e.g. blue eyes are a variant of eye colour)
what are genes?
units of inheritance
what is independent assortment?
the idea that each gene at a single location on a pair of chromosomes is equally likely to be transmitted when gametes form
what are gametes?
sex cells - egg and sperm cells
what is a chromosome?
a linear body in a cells nucleus that appear during cell division and replicate
what are cells?
basic unit of life for all organisms
what is a prokaryote?
cells with no nucleus/internal components
what is a eukaryote?
cells containing a nucleus / internal components separated by membranes
what is a nucleus?
a nucleus contains genetic material (chromosomes)
how many chromosomes do humans have?
46 chromosomes / 23 pairs
what is MITOSIS?
the division of somatic/body cells - produces 2 exact copies of parent
2n -> 2n + 2n (all with 46 chromosomes)
what is MEIOSIS?
division of gamete cells - produces four haploid cells
2n -> n + n + n + n (daughter cells have HALF chromosomes, 23)
what forms a zygote?
a zygote is formed after meiosis when two haploid cells (sperm and egg) come together
what is a zygote?
a single cell that divides over and over to produce cells that make up a human body
what are alleles?
different forms of genes
describe homozygous vs heterozygous
homozygous: same alleles (aa or AA)
heterozygous: different alleles (Aa)
what is a genotype?
the alleles that are carried by an organism
what is a phenotype?
physical/observable characteristics
what are the two backbone components of DNA?
sugar and phosphate
what are the 4 nucleotide bases?
- adenine and thymine
- cytosine and guanine
what happens if there is errors in replication?
there can be mutations
what is the role of proteins in the body?
regulate gene expression, structure of cells, regulate immune system, etc.
what is the function of a protein determined by?
its shape
what do regulatory genes do?
turn genes on and off, regulate how much/what protein is made
what is the role of RNA?
to manufacture proteins and help genes function
what are the 3 steps of DNA coding?
- DNA is transcribes into mRNA (messenger RNA)
- mRNA carries the message to ribosomes
- mRNA is transcribes into amino acid sequences by tRNA (transfer RNA)
what nucleotide base is substituted on mRNA?
thymine becomes uracil
when does transcription occur?
when an activator is bound (lactose is present, glucose is not present) and a repressor is unbound
(when a repressor binds: there is no lactose and glucose is present) (a-l) (r-g)
