B5.1 Flashcards
Species
group of organisms with SIMILAR characteristics that can interbreed to produce fertile offspring
Variation
Differenceoff of phenotype within a species caused
1) due to mutations in the DNA =genetic
But can also be some environmental things like tan, height due to food received etc = environment
Mixture of both
Genotype
Phenotype
Allele
Genome.
Gene
The combination of alleles in an organism
The appearance of an organism
The different types of the Same gene
Length of dna that codes for a protein
All the genetic material of an organism
What is variation determined by?
Environment and genetic
Some just genetic= like eye colour
Some just environmental = like accent
Some bith= height, maximum height out by genes , but whether you reach that height or not is dependent on how much food you eat
Continuous and discontinuous data
How many genes control them
What graph
Which are influenced by environmental factors
Continuous involve things like weight, height leaves on tree, length of hair , as they CHANGE over time and have a minimum and maximum value, and often effected by environment . They are controlled by a few genes and you should use a LINE GRAPH.
Discontinuous data is like variation falling into Distinct groups, and don’t change like blood type, eye colour, skin Couleur, gender . Controlled by a one/2 at most and use a BAR GRAPH TO SHOW IT… also not influenced by environmental factors
Mutations how happen ?
Problems ?
What happens in non coding sections ?
Mutations are caused when the sequences of bases are ALTERED.
This happens when dna bases are ALTERED, ADDED OR DELETED.
Mutations are rare random change, and so a genetic VARIANT IS PRODUCED. Eg: the codons will now code for a different amino acid, and the sequence of amino acids change too= different changed protein
they are caused by
- uv rays from the sun
- ionising radiation like gamma and x rays
- FANDOM COPYING ERRORS in mitosis
Are al, mutations leading to bad?
2) most cases the mutation will code for the same amino acid, meaning the phenotype is not changed
- some may change the phenotype but doesn’t harm us (like dimples) neutral
- sometimes it cns be beneficial, and this is how natural selection works
- some are bad. They can cause the uncontrollable division if cells: cancer
- can cause abnormal protein channels, meaning some molecules csn’t be transported properly like salts and water (cystic fibrosis)(here can cause breathing problems)
- cause change to shape of proteins = enzyme bruh= pku
- change to shape can also have other bad effects . FOR EXAMPLE SICKLE CELL ANAEMIA. Where blood cells can’t carry oxygen that well,
What happens if mutations occur in non coding parts of dna
Non coding parts of dna control whether the gene gets expressed at all. If a mutation occurs, the gene may not be transcribed into dna, and so therefore a protein is never produced- resulting in problems
Or happen too much / turn on switched off genes
(Non coding dna is based that don’t code for a gene …)
asexual
What is it
Asexual reproduction is where the new organism coantians identical genes to the parent cell- a clone .
- Spider plants, potato plants daffodils. Remember potato plants produce tubers where a new plant can grow from, daffodils they make bulbs where new plants can grow from.
- some animals like starfish can do
Advantages
- if the organism is well adapted to an area, then all its offspring will be too.
- they require themselves so it means time isn’t wasted looking for mate, and they can reproduce when favourable thus (not restricted to finding partner first)say a lot of food is available.
- happens quickly, so they can colonise an area quickly
Disadvantage
- no genetic variation- if a condition threatens survival for the organism all the organisms will be in trouble, leading to the destroyment of the species
Sexual
What happens if an organism can do both?
When two parents genetic information fuse to create a genetically different child and it results in VARIATION. It is when sperm and egg fuse in fertilisation and create ZYGOTES. Or when pollen cell and egg cell fuse in plant…
Advantages-
- creates genetic variation, meaning more likely an organism will inherit an adaptation which means these organism can survive changes made to environment, allowing the population to continue. (They have characteristics to survive, leads to evolution)
Disadvantage is
- two parents needed- so time is spent loooking for mate and is problem if organisms are isolated.
- reproduction is slower, so only few offspring
2) they will be more likely to survive as they can take advantage of both and be more succesful.
Meiosis
Will genome be different?
1) chromosomes are copied.
2) line up in middle
3) pulled apart to separate ends. WHEN THIS HAPPENS, sections of dna are often swapped, causing changes in genes as each cell will have some of FSTHER genes and some mother, but not equal amounts.
4) cell splits by membrane pinching in ,
5) second stage the chromosomes line up again in the centre
6) pulled apart to opposite ends
7) this times nothing happens
8) membrane pinches in they split. Nucleus formed . A single copy of each chromosomes is in each cell now, with 23 in total . Haploid
Meiosis results in 4 genetically different daughter cells .
How does fertilisation happen.
Will genome be different for everyone.
?
Sexual reproduction preduces genetically different gametes. Two gametes fuse to make a diploid cell called a zygote , which divides by mitosis to make an embryo which develops into an organism . It now has mixture of characteristics from mother and father.
Genome will be different for everyone except IDENTICAL TWINS.
What must you do in genetic cross diagrams?
1) phenotype of parents
2) genotype of parents
3) punnet square cross
4) genetirype of offspinrg
5) PHENOTYPE OF EACH OFFSPRING
Gregor Mendel
His experiments
What DIDNHE CINCLUDE LESRN THIS .
He did pea plant experiment. He crossed tall pea plants with short pea plants, and all of the offspring were tall.
- then he crossed those with each other. The result was 75% were all, but 25% were short.
- he then determined that tall was a dominant allele, short wasn’t.
- he did similar experiments with green and yellow, and wrinkled and git the same result
He concluded
1) Characteristics are determined by HEREDIATRY UNITS
2) these units are passed on unchanged from both parents
3) units can be dominant or recessive and if both were represented the dominant one takes over
Why do we have two alleles
Because we have two copies of every use we received from our parent. Here if they are the same they code for the same thing but if different brains then one is favoured based on recessive it dominant
