Genetics Flashcards
what are advantages of asexual reproduction?
+ can produce offspring really quickly-> colonise an area
+ only need one parent -> reproduce whenever confirms are favourable and less energy & time spent
what are disadvantages of asexual reproduction
- no genetic variation > whole population will be affected if disease occurs& reduces ability to adapt to new environmental conditions
what are advantages of sexual reproduction
- genetic variation > have characteristics that help them survive in environmental changes
- can use selective breeding > organisms with desirable traits can be produced
what are disadvantages of sexual production
- two parents are required > diffusion to reproduce in endangered species or those who live solitary lifestyles
- more energy and time needed > fewer offspring are produced
what is sexual reproduction?
gametes from each parent fuse during fertilisation to for a. diploid zygote which undergoes cell division to become an embryo
what are gametes
what is asexual reproduction.
reproduction where cells divide by mitosis to form two genetically identical diploid cells known as daughter cells
What is the first stage of meiosis?
- interphase - duplicate dna so one arm of each x chromosome is exact copy. 1/2 chromosomes are from the father and the other is from mother
- first cell division > chromosomes line up in the middle
- pairs of chromosomes are separated and move to the opposite sides of the cell > each cell has a copy one each chromosome
- each cell has a mixture of parent chromosomes > genetical variation
what happens during the second stage of meosis
- chris omes lime uo in the middle then are pulled apart to opposite sides of cell
2.four unique haploid cells are productsd > each gamete is genetically different
why is meosis important for sexual reproduction?
- increases genetic variation
- ensures resultant zygote is diploid
what are similarities of mitosis and meosis?
what are differences between mitosis and meosis?
describe what dna is.
polymer of nucleotides made of two strands coiled to form a double helix
- strands are linked by series of complementary base pairs joined together by weak hydrogen bonds
what do nucleotides consist of?
sugar and phosphate groups alternating to form a backbone with one of the four bases (A > t, c>G) attached to the sugar
what’s a chromosome?
ling coiled up molecules of dna
gene
section of dna on chromosome that codes for particular protein
what’s a genome?
all of organisms genetic material /dna
How can you extract dna from a fruit?
- Grind fruit tissues > break cell wall so DNA is released
- add saline solution > neutralise DNA charge and becomes less soluble
- add detergent > breaks down lipids of cell membrane surrounded DNA
- filter mixture to separate froth and insoluble bits
- add protease enzyme > catalyse breakdown o
- add ice cold ethanol > form precipitate so white strands of dna are left
explain how a gene codes for a protein
- a sequence of three bases in a gene forms a triplet
- each triplet codes for an amino acids
- order of amino acid determines the structure ( how they fold) to produce specially shaped proteins & function
why is folding of amino acids important in proteins such and enzymes?
it determines the shape of the active site which is highly specific to the shape of the substrate
what is protein synthesis?
formation of protein from a gene