Genetics Flashcards
What is DNA?
dioxyribonucleic acid that stores the hereditary information for organisms
What is a gene?
segments of DNA that code for a specific peice of information/trait
What is the difference between diploid and haploid cells?
Diploid - cells have two copies of each chromosome
(duplicated)
Haploid - cells with one copy of each chromosome (non-duplicated)
Define chromosomes and chromotids?
chromosomes - individual coiled up molecules of DNA
chromotids - single arm in the duplicated chromosome
What are the three stages in the cell cycle?
inter-phase, mitosis and cytokenesis
What happens during inter-phase?
period between cell divisions
cell undergo their normal activities
3 sub-stages are G1 phase, synthesis phase and G2 phase
in s phase DNA is replicated for cell division
What is mitosis? How many stages are there?
process of cell division
there are four stages
What happens during pro-phase?
chromatin coils to form chromosomes to shorten and thicken
What happens during meta-phase?
the micro-tubules line up on the middle of the cell preparing to split
What happens during ana-phase?
chromatids separate and move to the outside of the cells pulled by spindles
What happens during tele-phase?
reforms to make two nuclei and a wall forms between them
What happens in cytokineses?
The cytoplasm and organelles are divided between the daughter cells
What are the 8 stages of meiosis?
prophase I, metaphase I, anaphase 1, telephase 1
prohase II, metaphase II, anaphase II, telephase II
How many cells are produced by meiosis?
Four
What happens in meiosis I and II that is different from mitosis?
In meiosis I, the homologous pairs are pulled are part while the sister chromatids stay together
- in meiosis II, the sister chromatids are split
- the number of chromosomes in the daughter cells is 23
What is an allele?
- the possible forms of a gene
- some are more dominant over the others
ex. brown hair and blonde hair
Define genotype
the genetic makeup of an individual
ex. BB, Bb, bb
Define phenotype
the physical appearance of an individual
ex. brown or blue eyes
who was Gregor Mendel and what did he contribute to biology?
-First person to look at dominance, segregation and independent assortment
How many traits do dihybrid crosses look at?
2
define incomplete dominance
- where neither trait is dominant so they both inluence the final colour, creating a blend
ex. white + yellow guinea pig = cream babies
define codominance
- neither trait is dominant so both alleles are expressed fully
ex. black + white cat = black and white cat
What forms of dominance do blood types have?
dominant/recessive (Iai) and incomplete (IaIb)
What is a pedigree?
a chart of genetic relationships based on several generation that shows certain traits, used instead of test crosses, helps determine the dominance of the allele
