4092936
Description
Flashcards by Kit Sinclair, updated more than 1 year ago
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Created by Kit Sinclair
over 8 years ago
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| Question | Answer |
| How many pairs of chromosomes are there in a body cell? | 23 pairs (46 chromosomes) |
| Give an example of a genetically inherited characteristic | gender, eye colour, hair colour |
| Give an example of an environmentally inherited characterisitc | Bruises, scars, hair length |
| Give an example of a characteristic that is both environmentally and genetically inherited | Height - affected by genes and also diet/overall health |
| What is in the nucleus? | Genetic information in the form of genes which contain DNA |
| What are proteins made of? | Ribosomes |
| Gene | contains DNA which codes for a specific sequence of amino acids to be joined to make proteins |
| How is DNA structured? | Double helix |
| What are the base pairs in DNA? | AT and CG |
| How can DNA be used? | - DNA fingerprinting-test bodily fluids left at a crime scene - DNA testing - use cheek swabs to work out relationships |
| Chromosome | Found in the nucleus. Carry coded information in the form of a gene |
| Amino Acids | Molecules that join together to make proteins |
| Cell Membrane | Control the movement of substances in and out of a cell |
| Cytoplasm | Where many chemical reactions take place |
| DNA | chemical that chromosomes are made of |
| clone | exact genetic copy |
| gametes | sex cells |
| fertilisation | when the egg and sperm fuse together |
| zygote | fertilised egg cell |
| allele | different version/form of the same gene |
| asexual reproduction | there is only one parent and the offspring is a genetically identical clone |
| sexual reproduction | 2 parents, variety in offspring, gametes made and cell fusion involved |
| mitosis | cell 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 |
| meiosis | produces 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 |
| What 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) |
| Uses of stem cells | Stem cells can treat conditions like paralysis, among others, by becoming nerve cells Also treats leukemia and Parkinsons |
| How is gender inherited through sex chromosomes? | XY = male XX = female |
| What is a dominant allele? | An allele that will show itself even if there is only one present in a pair |
| What is a recessive allele? | An allele that will only show itself if there are two present in a pair |
| Phenotype | The physical expression of our genotype (the type of gene makeup you have) |
| Homozygous | Having two of the same allele |
| Heterozygous | Having two different alleles |
| Who 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 |
| Embryo Screening | Checking 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" |
| Tissue Culture | Tissue sample scraped from plant and placed in Agar containing nutrients; the samples develop into tiny plantlets which are then planted |
| Embryo Transplant | The 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 |
| Adult Cell Cloning | Body 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. |
| Genetic Engineering | A 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 |
| Evolution | the often gradual changes in organisms over a long period of time |
| Extinction | - disease - sudden catastrophic event - over poaching - habitat loss - competition |
| Lamarkism | acquired 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) |
| Darwinism | also 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 |
| Evidence for evolution | - fossil record - changes/differences in genes - DNA of species |
| Fossilisation | organism 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 |
| What prevents decay? | - rock - amber - ice - tar |
| Why 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 |
| What 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 |
| Speciation | the formation of a new species |
| Species | Two animals are considered different species if they cannot produce fertile offspring |
| How 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 |
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