inheritance Flashcards
(16 cards)
describe the structure of a nucleotide
- phosphate
- attached to a sugar
- 1 of 4 bases attached to sugar
- bases are A,T,G,C
differences between process of mitosis and meiosis
- mitosis 2 daughter cells, meiosis 4 daughter cells
- one cell division in mitosis, 2 divisions in meiosis
- mitosis produces cells with two of each chromosome, but
meiosis produces cells with one of each chromosome - mitosis produces genetically identical cells, but meiosis
produced genetically different cells - meiosis involves gametes, mitosis other body cells
similarities between mitosis and meiosis
- DNA doubles / copies / replicates
- increase in the number of mitochondria / ribosomes /
sub-cellular structures
The embryo will then be lost from the woman’s body several days later.
Explain why the woman may not notice this has happened.
embryo is (very) small
(so) embryo not seen / felt
or
lost in normal menstrual flow
Why are the children not genetically identical?
- different egg / sperm each time
- genes from two parents
- each gamete / egg / sperm has different alleles / genes / DNA /
genetic information
describe process of natural selection
- variation
- better adapted to survive
- pass on favourable alleles
describe how a change of one of the bases in the gene for an enzyme could affect the functioning of an enzyme
- change in a base changes the triplet/codon
- this changes the amino acid it codes for
- so there will be a different sequence of amino acids
- means the polypeptide will fold into a differently shaped protein/enzyme
- the protein/enzyme may have a differently shaped active site
- so it may no longer be complementary to the substrate
- which would mean it couldn’t form an enzyme-substrate complex
- so it couldn’t catalyse the reaction as well / the rate would be lower
describe the structure of DNA
- polymer made up of two strands
- forming a double helix
explain how portions of genes that don’t code for proteins can still influence phenotype
- non-coding DNA causes changes in gene expression
- can determine whether genes are expressed or not and if proteins are made or not
give two reasons it was hard to prove who was correct in 1800s darwin / lamarck
- not enough fossil evidence
- DNA not yet discovered so inheritance not understood
type of fossils produced by plants
imprints
explain why plant fossils are rarer than animals
- all soft parts which decay
- conditions for formation are rare
natural selection
- random mutation in DNA
- causes different protein to be made
- so more variation
- animals with mutation more likely to…(favourable characteristic)
- get more food / avoid being eaten
- out competing others without mutation
- more likely to survive and reproduce by natural selection
- passing on allele to offspring
- repeated over many generations
advantage of binomial system
universally understood
explain how sexual reproduction leads to this variation in flower colour
- Genetic material from both parents combines during fertilisation
- Offspring inherit different combinations of alleles, leading to new traits
embryo screening ad / disad
- reduces chance of passing on disease
- could lead to embryo being destroyed
