the characteristics/ observable traits you have

what can you use to predict the outcomes of crosses between individuals for their combination of alleles?

an inherited disorder of the cell membranes, caused by a recessive allele (f)

as it is a recessive allele, a homozygous pair is needed to have the condition 

why are some people carriers of cystic fibrosis?

a genetic disorder where a baby is born with extra fingers or toes, caused by a dominant allele (D)

where during IVF it is possible to analyse its genes, or to get an embryo from the womb and test for disorders

in the womb- termination of pregnancy, IVF- destroying of embryos with "bad" alleles

stops suffering, treatments for disorders costs the government, there are laws which stop it going too far

what are arguments for embryonic screening?

it increases prejudice, its expensive, people may want to pick "desirable" characteristics 

what are arguments against embryonic screening?

what is most variation in the phenotype caused by?

a rare, random change in DNA that can be inherited 

it is altered, which produces a genetic variant and can lead to changes in the protein it codes for

what happens to the gene during variation?

usually no effect, however sometimes can determine phenotype 

how big of an effect do genetic variants have on the phenotype?

all of todays species have evolved from the simple life forms that first started to develop over 3 billion years ago

that those with the most suitable characteristics for the environment would be more successful competitors and more likely to survive, therefore reproduce and pass on characteristics

what is the idea of survival of the fittest?

the discovery of genetics, looking at fossils, the study of bacteria becoming resistant etc. 

what new discoveries support and develop Darwin's theory?

the development of a new species, where phenotype changes so much that a new species is formed 

when populations of the same species become reproductively isolated, and can't interbreed to form fertile offspring 

environmental change, habitat destruction, new predators, new diseases, inability to compete, catastrophic events 

artificially selecting the organism with the beneficial genes

select the ones with the best characteristics, breed them with each other, select the best offspring and breed them together, continue process

what is the process of selective breeding?

reduces the gene pool (no different alleles- inbreeding), can cause health problems as theres a higher chance of inheriting harmful genetic defects when the gene pool is limited, if new disease appears, due to lack of variation all will succumb

what are drawbacks to selective breeding?

the transfer of genes responsible for a desirable characteristic from the genome into another organism

useful gene isolated using enzymes, inserted into a vector which is introduced to the target organism and the useful gene is inserted into its cells 

explain the process of genetic engineering

produce human insulin for diabetes, modify crop genes and improve quality, gene therapy etc

people are worried that changing an organisms genes can create unplanned problems which will get passed onto future generations

why is genetic engineering controversial?

increases yield- more food, crops can be engineered to contain nutrients that developing nations are missing, often has little problems

affects the number of wild flowers and reduce farm land biodiversity, may not fully understand the effect of eating modified crops, may develop allergies, transplanted genes may get into natural environment (e.g herbicide picked up by weeds)

remains of organisms that are found in rocks

from gradual replacement by minerals, from casts and impressions- buried in soft material and decaying, leaving a cast of itself, from preservation in places with no decay- eg. peat bogs, glaciers, amber (no oxygen or moisture so decay microbes cant survive)

what are the 3 ways in which fossils form in rocks?

many early forms of life were soft-bodies and wouldve decayed away completely

random mutations, spread quickly as bacteria reproduces rapidly and can evolve quickly

what causes resistant strains of bacteria?

due to the overuse and inappropriate use of antibiotics 

why is the problem of antibiotic resistance becoming a bigger problem?

a system of classification by Carl Linnaeus in the 1700s, which grouped living things according to characteristics and their structures

kingdoms, phylum, class, order, family, genus, species 

what is the order of the Linnaean system?

1- Archaea- primitive bacteria, found in extreme conditions. 2-bacteria- true bacteria e.g E.coli  3-Eukaryota- broad range of organisms including plants, animals, protists and fungi 

what does the three-domain system consist of?

a way in which organisms are named, the first part being the genus and the second part being the species 

what can you use to show evolutionary relationships?

deoxyribonucleic acid- the chemical that all genetic material is made from

in chromosomes, in the nucleus. DNA is 2 strands coiled in a double helix shape 

a small section of DNA on a chromosome, that codes for a particular sequence of amino acids, to make a specific protein

how many amino acids are used to make up proteins?

the set of genetic material in an organism

allows scientists to identify genes linked to disease, develop effective treatments, and trace migrations, along with when populations split in different directions

why is understanding the human genome important?

where genetic material from 2 parents produce genetically unique offspring

how are gametes produced in sexual reproduction?

23, so forms a full set (46) during fertilisation

in humans, how many chromosomes does a gamete contain?

where there is only one parent, that produces genetically identical offspring, as there is no mixing of chromosomes or fusion of gametes

where does asexual reproduction take place?

a process of cell division which results in 4 daughter cells, involving 2 divisions, to make gametes with only half the original number of chromosomes

1-cell duplicates genetic information, forming two armed chromosomes and arranging them into pairs. 2-pairs line up in middle. 3-pairs pulled apart, each new cell has mothers+father chromosomes. 4-chromosomes line in middle again and arms pulled apart. 5- results in 4 genetically different gametes 

the cell produced by gamete fusion divides by mitosis to replicate itself, and repeats to produce new cells in an embryo

the 23rd pair of chromosomes are labelled XX (female) or XY (male 

what can you use to find the probability of getting a boy or a girl?

what is the probability of the childs sex?

different versions of genes- you have 2 versions of every gene in your body (one on each chromosome in a pair)

heterozygous (different) and homozygous (same)

what words describe 2 of the same, and two different alleles?

dominant needs just 1 dominant allele, but recessive needs both alleles to be recessive (e.g cc not Cc) 

what is needed for an organism to display a recessive characteristic vs a dominant characteristic?

B6- Inheritance, Variation and Evolution

Flashcards

variation and inheritance

GCSE REVISION GUIDE!! Aesthetic | Summaries | Visual Learners

History of Genetics Notes

Genome, chromosomes, DNA and genetics

B6: Inheritance, Variation, Evolution

variation and inheritance mind map