Inheritance, Varation And Evolution- Paper 2 Flashcards
What does DNA stand for and what is it? and what is it shaped like?
.DNA polymer deoxyribonucleic acid.
.all of the genetic material in a cell is made up from.
.chromosomes up two strands coiled together shape of a double helix.
What does DNA do where is it found and what is it made up of and how many?
.determines what inherited characteristics you have.
.nucleus long structures (chromosomes.)
.Chromosomes normally come in pairs. 46 total 23 each
What does a gene do and what are they (2) and how do they complete their job? (3)
1)gene small bit of DNA in chromosomes
2) gene codes particular sequence amino acid put together make specific protein.
1) 20 amino acids are used, different proteins.
2) Genes tell cells what order to put the amino acids together
3)determines what proteins the cell produces
What is a Genome?
.Genome=entire set of genetic material in an organism.
(Scientists have worked out the complete human genome.)
Why is knowing the whole human genome important? (3)
1) identify genes in genome linked to different types of disease.
2) Knowing genes are linked to inherited diseases understand better, develop treatments.
3) genomes to trace the migration of certain populations of people.
.humans are descended from a common ancestor in Africa
.populations split off in a different direction and what route.
What is DNA made of? And why is it important?
1)polymers lots repeating units= nucleotides.
2) Each nucleotide consists sugar, a phosphate group and one base
3)Nucleotide form a “backbone’ to the DNA strands.
.sugar and phosphate groups alternate.
What are the non coding parts of DNA?
.switch genes on and off, control whether or not a gene is expressed (used to make a protein).
The process of making proteins? 6
1)Proteins are made in the cell cytoplasm in ribosomes.
2) ribosomes use the code in the DNA.
3) mRNA - made by copying the code from DNA. (acts as a messenger between the DNA and the ribosome.)
4)correct amino acids are brought to the ribosomes in the correct order by carrier molecules.
5)chain of amino acids has been assembled
6)it folds into a unique shape which allow protein to perform the task.
What types of proteins (3)?
1) ENZYMES - biological catalysts to speed up chemical reactions in the body. E.g. amylase
2) HORMONES - used to carry messages around the body. E.g. insulin
3) STRUCTURAL PROTEINS - are physically strong. E.g. collagen
What are Mutations? 2 What incases the 2 chance of mutations?
1)mutation random change in an organism’s DNA. can be inherited.
2) occur continuously. chance of mutation is increased by exposure certain substances or some types of radiation.
What does mutations do? what happens to proteins?
.change the sequence of the DNA bases in a gene=genetic variant
.codes sequence of amino acids that make up a protein lead to changes in the protein. often very little effect
. mutation will code for an altered protein change in its shape. affect its ability to function.
What happens if a mutation affects a protein? ENZYMES, STRUCTURAL, NON-CODING
1)enzyme’s active site is changed,
substrate no longer bind to it.
2) Structural proteins like collagen lose their strength shape is changed
3)mutation in the non-coding DNA, alter how genes are expressed.
What are the types of mutations? 3
.Insertions= new base inserted into sequence change more than one amino acid knock-on effect on bases further on in the sequence.
.Deletions= random base in DNA base sequence where it shouldn’t be. deleted from the DNA base sequence.
.Substitution= mutations are when a random base in the DNA base sequence is changed to a different base.
Sexual reproduction?
Sexual reproduction genetic information from two organisms (a father and a mother) combined produce offspring genetically different to either parent.
How does Sexual Reproduction Produces Genetically Different Cells? 4
1) mother and father produce gametes by meiosis egg and sperm cells
2) gamete contains 23 chromosomes - half the number of chromosomes in a normal cell.
3)egg and sperm fuse together (fertilisation) to form cell with 48 C= zygote
4) inherits features from both parents - it’s received mixture chromosomes=variation
What is Asexual Reproduction?
one parent so the offspring are genetically identical to that parent.
How Asexual Reproduction happens? 2 and who reproduces this way? 3
1) mitosis - ordinary cell makes a new cell by dividing in two.
2) new cell has same genetic information parent cell=clone.ONE parent. no variation
Bacteria, some plants and some animals reproduce asexually.
How Gametes Are Produced by Meiosis and where does this happen? 2
1)cells divide by meiosis, have half the original number of chromosomes
2)involves two cell divisions. only happens in the reproductive organs
Process of meiosis?
1)Produces Cells With Half Normal Number of Chromosomes
2)Before cell starts to divide, duplicates its genetic information, forming two armed chromosomes - exact copy of other arm.
3)chromosomes arrange themselves into pairs. first division in meiosis the chromosome pairs line up in the centre of the cell.
4)pairs are then pulled apart so each new cell only has one copy of each chromosome. father’s mother’s
5)second division, chromosomes line up again in the centre. the arms of the chromosomes are pulled apart.
=four gametes identically different
How do Cell Produced by Gamete Fusion Replicates Itself? 3 steps
1) two gametes have fused during fertilisation, the resulting new cell divides by mitosis copy of itself.
2) repeats many times to produce lots of new cells in an embryo.
3) embryo develops, cells then start to differentiate different types of specialised cells make up a whole organism.
Sexual Reproduction Advantages? 2
1)variation in the offspring- increases the chance of a species surviving a change
2)better adapted to the environment have a better chance of survival, likely to breed successfully and pass the genes for the characteristics on.
Asexual Reproduction Advantages? 4
1)one parent.
2) less energy don’t have to find a mate.
3) faster
4) Many identical offspring can be produced in favourable conditions.
Reproducing using asexual and sexual reproduction in malaria 3, fungus 3?
1)female mosquito carrying the parasite bites a human, parasite transferred
2)reproduces sexually mosquito
3)asexually when it’s in the human host.
1) fungus sexually and asexually.spores, new fungi land in a suitable place. Spores can be sexually and asexually.
Chromosomes Control Whether You’re Male or Female?
.Males have an X and a Y chromosome: XY ( Y chromosome=male characteristics.)
.Females have two X chromosomes: XX
Gametes chromosomes for sex?
. making sperm, the X and Y chromosomes are drawn apart in the first division in meiosis (50%)
=all the eggs have one X-chromosome.
How to draw Genetic Diagrams Show the Possible Combinations? 3
1)Genetic diagrams=possible genetic outcomes cross together different genes
2) possible alleles from one parent down the side, and those the other parent along the top.
3) middle square you fill in the letters
pairs of letters=possible combinations.
What are Characteristics Controlled by, what is an alleles and how many in your body? 4
1) genes inherit=Different genes control different characteristics.
2) most characteristics are controlled by several genes interacting.
3) genes exist different versions=alleles
4) two versions (alleles) of every gene in your body
heterozygous and Homozygous?
.organism has two alleles for a particular gene that are the same= homozygous. 2 same allels
If its two alleles for a particular gene are different, then it’s heterozygous. 2 diffrent allels
Recessive and dominant alleles how do you show this?
. two alleles are different, only one can determine what characteristic is present.
. The allele for characteristic that’s shown is called the dominant allele (use a capital letter)
.The other one is called recessive (lower case)
What are genotype and phenotypes?
.genotype is combination of alleles you have.
.alleles determine what characteristics you have (phenotype.)
How do Genetic Diagrams Show the Possible Alleles of Offspring?
1) superpower hamster must have the genotype bb. But a normal hamster could be BB or Bb
2) Here’s what happens if you breed from two homozygous hamsters:
How can Embryos Can Be Screened for Genetic Disorders? 3
1) IVF=Before being implanted, remove a cell from each embryo and analyse its genes.
2) genetic disorders detected.
3)embryos with ‘bad’ alleles would be destroyed.
The development of the understanding of chromosomes? 3
1)1800s=chromosomes. observe behaved cell division.
2) 1953=structure DNA was determined- how genes work.
3)20th century=similarities chromosomes Mendel’s “units” acted-genes.
How to sample randomly to find a population of something?
Percentage Change?
.When investigating the change in a variable, you may want to compare results that didn’t have the
same initial value. One way to do this is to calculate the percentage change.
Disadvantages of selective breeding? 3
1.reduces the gene pool - number of different alleles in population=inbreeding.
2.Inbreeding high chance inheriting harmful genetic defects= variation low.
3. low genetic varation= not survive new disease
CUTTINGS process? 3 adv
.plant produce genetically identical copies (clones) parent plant.
.produced quickly and cheaply.
.simpler method than tissue culture.
