Inheritance Flashcards
DNA
chemical that all of genetic material in a cell is made up of
name of a DNA molecule structure
double helix
gene
small section of DNA found in chromosomes
each gene codes for…
a particular sequence of amino acids which are put together to make a specific protein
how many amino acids are used and make up thousands of different proteins
20 amino acids
what do genes tell cells to do
tells cells in what order to put amino acids together
genome
the entire set of genetic material in a organism
why is understand the human genome very important
- allows scientists to identify genes in the genome that are linked to different types of diseases, which helps us develop treatment for it
- scientists can work out when new populations split off in a different direction and where they went
sexual reproduction
genetic information from two organisms (father and mother) is combined to produce offspring containing mixture of parents genes (why we inherit family features)
i’m sexual reproduction what do the mother and father produce
gametes by meiosis (egg and sperm cells in animals)
how many chromosomes does each gamete contain
23 (half number of chromosomes in a normal cell)
the mixture of genetic information that is created when two organisms sexually reproduce produces what
variation in the offspring
asexual reproduction
- only one parent
- no fusion of gametes
- no mixing of chromosomes
- no genetic variation (offspring are genetically identical)
asexual reproduction happens by…
mitosis, ordinary cell makes new cell by dividing in two
examples of asexual reproduction
- bacteria
- some plants
- some animals
differentiation
process by which a cell changes to become specialised for its job, carry out specific functions
used to repair and replace cells (skin or blood cells)
how many matched pairs of chromosomes are there that control your characteristics
22/23 pairs
what are the 23rd pair of chromosomes labelled and that do they do
- labelled XY or XX
- decide your sex, turn male or female
when making sperm what happens to the X and Y chromosomes
drawn apart in first division in meiosis
what is the percentage each sperm cell gets an X and Y chromosome
- X: 50%
- Y: 50%
what must both it’s alleles be if an organism wants to display a recessive characteristic
recessive (bb)
what must both it’s alleles be if an organism wants to display a dominant characteristic
BB or Bb
because the dominant allele (B) overrules the recessive allele (b)
genotype
combination of alleles you have
what is “b”
recessive, superpowers
what is “BB” or “Bb”
dominant, normal and boring behaviour
cystic fibrosis
- a genetic disorder of the cell membranes
- results in the body producing a lot of thick sticky mucus in the air passages and in the pancreas
cystic fibrosis allele
- recessive allele
- carried by about 1/25 people
can a person with one copy of the allele have cystic fibrosis
- no, they’re known as carriers
- both parents must be either carriers or have the disorder themselves for a child to have it (still 1/4 chance)
polydactyly
genetic disorder where a baby’s born with extra fingers or toes
polydactyly is caused by what
- a dominant allele
- can be inherited if just one parent carries it (50% chance of child getting it if other parent does not have it)
reasons to be against embryonic screening
- implies that people with genetic problems are “undesirable” could increase prejudice
- screening is expensive
- don’t want people to be too picky on what features their child will have
for embryonic screening
- help stop people suffering
- laws to stop it going too far, parents can’t select sec of their baby