Flashcards
Genetics
Flashcards do conjunto (51)
- 1How many pairs of chromosomes are there in a body cell?23 pairs (46 chromosomes)
- 2Give an example of a genetically inherited characteristicgender, eye colour, hair colour
- 3Give an example of an environmentally inherited characterisitcBruises, scars, hair length
- 4Give an example of a characteristic that is both environmentally and genetically inheritedHeight - affected by genes and also diet/overall health
- 5What is in the nucleus?Genetic information in the form of genes which contain DNA
- 6What are proteins made of?Ribosomes
- 7Genecontains DNA which codes for a specific sequence of amino acids to be joined to make proteins
- 8How is DNA structured?Double helix
- 9What are the base pairs in DNA?AT and CG
- 10How can DNA be used?- DNA fingerprinting-test bodily fluids left at a crime scene
- DNA testing - use cheek swabs to work out relationships - 11ChromosomeFound in the nucleus. Carry coded information in the form of a gene
- 12Amino AcidsMolecules that join together to make proteins
- 13Cell MembraneControl the movement of substances in and out of a cell
- 14CytoplasmWhere many chemical reactions take place
- 15DNAchemical that chromosomes are made of
- 16cloneexact genetic copy
- 17gametessex cells
- 18fertilisationwhen the egg and sperm fuse together
- 19zygotefertilised egg cell
- 20alleledifferent version/form of the same gene
- 21asexual reproductionthere is only one parent and the offspring is a genetically identical clone
- 22sexual reproduction2 parents, variety in offspring, gametes made and cell fusion involved
- 23mitosiscell division for growth and repair - 1 parent cell with chromosomes that replicate themselves within the cell; the cell then splits into two daughter cells with the same chromosomes
- 24meiosisproduces gametes - the chromosomes replicate themselves with a small part of one pair attached to the other; the cell then divides into 4 daughter cells with half the number of chromosomes
- 25What are stem cells and where do they come from?Stem cells are cells that can change what sort of cell they are (differentiate)
- embryos (embryonic)
- blood of umbilical cord (foetal stem cells)
- bone marrow (adult stem cells) - 26Uses of stem cellsStem cells can treat conditions like paralysis, among others, by becoming nerve cells
Also treats leukemia and Parkinsons - 27How is gender inherited through sex chromosomes?XY = male
XX = female - 28What is a dominant allele?An allele that will show itself even if there is only one present in a pair
- 29What is a recessive allele?An allele that will only show itself if there are two present in a pair
- 30PhenotypeThe physical expression of our genotype (the type of gene makeup you have)
- 31HomozygousHaving two of the same allele
- 32HeterozygousHaving two different alleles
- 33Who is Gregor Mendel?An Austrian monk who bred thousands of pea plants to study their genetics, however his work was not recognised until the early 20th century because he was not a well respected scientist
- 34Embryo ScreeningChecking the genetics of an embryo before it is born to see if it has any genetic diseases, however the screening could damage the embryo and lead to "designer babies"
- 35Tissue CultureTissue sample scraped from plant and placed in Agar containing nutrients; the samples develop into tiny plantlets which are then planted
- 36Embryo TransplantThe female/male with best genetics are bred and the embryo is split - each cell develops into an identical embryo and is implanted into a host mother
- 37Adult Cell CloningBody cell is taken from one animal and an egg cell from the other. Both cells have their nucleus removed and the nucleus from the body cell is implanted into the egg cell, which is then given an electric shock to start developing. The embryo is implanted into a host mother.
- 38Genetic EngineeringA desirable gene is "cut out" from the DNA of one cell using enzymes. The gene is then inserted into the DNA of another organism at an early stage of development - very controversial as the effects are unknown and it could lead to cross-contamination
- 39Evolutionthe often gradual changes in organisms over a long period of time
- 40Extinction- disease
- sudden catastrophic event
- over poaching
- habitat loss
- competition - 41Lamarkismacquired characteristics from an organism's life are inherited by offspring (in 1800s because of lack of evidence scientists were originally unsure if he was correct or not)
- 42Darwinismalso called natural selection/survival of the fittest, it suggests that animals with successful characteristics (due to genetic mutations) were the ones to survive and pass on these successful genes through the generations
- 43Evidence for evolution- fossil record
- changes/differences in genes
- DNA of species - 44Fossilisationorganism dies and the soft parts decay - the skeleton that is left slowly gets covered in sediment which starts to compact, causing fossilisation; over millions of years, geological movements cover and then uncover it with rock and the fossil is found
- 45What prevents decay?- rock
- amber
- ice
- tar - 46Why is the fossil record incomplete?- all fossils have not been founds
- soft parts of organisms decay
- rock moves or is worn away so fossil destoyed - 47What is the Peppered Moth?A moth that usually has a speckled appearance but due to a genetic mutation sometimes appears completely black - this version thrived during the Industrial Revolution because due to the smog it was very well camouflaged
- 48Speciationthe formation of a new species
- 49SpeciesTwo animals are considered different species if they cannot produce fertile offspring
- 50How does speciation occur?A species is separated into two groups by a geographical barrier and natural selection occurs - slowly the two groups evolve until they can no longer breed together and are considered different species
- 51—
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- GCSE Sciences (Biology) FlashCards sobre Genetics, criado por Kit Sinclair em 22-11-2015.
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- Kit Sinclair
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