BMAT Biology Flashcards
monohybrid cross
study of the inheritance of one characteristic
mating between two organisms with different variations at one genetic chromosome of interest
cystic fibrosis
recessive genetic disorder
inherited
affects lungs and digestive system
screening of cystic fibrosis
newborns: heel prick test done shortly after the neonate is born, to confirm a sweat test is done (salt levels are v high in those with CF), saliva test done
antenatal: amniocentesis or chorionic villus sampling
polydactyly
dominant genetic disorder
inherited
causes development of extra fingers and toes
screening of polydactyly
PGD- preimplantation genetic diagnosis (only done for people having IVF), amniocentesis
huntington’s disease
dominant disorder
inherited
affects neurones- degenerative
late onset
screening of huntington’s
PGD, amniocentesis, heel prick test, saliva test, chorionic villus sampling
process of genetic modification
1) copy of gene desired is taken from 1 organism
2) replication of desired gene
3) gene is inserted into a vector to form recombinant DNA
4) vectors transfered into another organism where it expresses the gene
examples of genetic modification
plant crops
insulin production using bacteria
process of natural selection
- variation w/in species
- causes differential survival
- those best adapted to survive w/ adv gene reproduce
- genes/ characteristics are passed onto next generation
sources of variation
genetic, environmental, combined
how does extinction occur
if organisms do not adapt quickly enough e.g climate change causing mass extinction
role of protease, lipase and amylase in digestion
protease- digests proteins into amino acids (called pepsin in stomach)
lipase-digests lipids into glycerol and fatty acids
amylase- digestion of carbohydrates into monosaccrides
respiration
the chemical process used to release energy
aerobic respiration
glucose + oxygen –> carbon dioxide + water
anaerobic respiration
done using enzymes, doesn’t use oxygen
ANIMALS: glucose –> lactic acid (+ATP)
YEAST: glucose –> carbon dioxide + ethanol
aerobic v anaerobic
aerobic: complete oxidation of glucose, products don’t have stored chemical energy, high energy release
anaerobic: partial oxidation of glucose, products have stored chemical energy, small but fast energy release
CNS
brain and spinal cord
structure and function of sensory neuron
send action potentials to relay neurons
have long dendrites and short axons
structure and function of relay neuron
pass action potentials between neurons (sensory and motor), found in brain
have short dendrites, can have long or short axons
structure and function of motor neuron
transmits action potentials away from CNS to periphery (effectors)
have short dendrites and long axons
synapse structure and function
a synapse is a gap between 2 neurons
1) in in the presynaptic neuron an action potential is carried and triggers vesicles in the nerve ending to release neurotransmitters
2) the neurotransmitters diffuse across the synaptic cleft where they bind to receptor molecules on the post synaptic neuron
3) this stimulates the post synaptic neuron to transmit the action potential
function of digestive system
to break down food into units that can be used for chemical reactions
the alimentary canal: mouth (has salivary glands), oesophagus, stomach, pancreas (produces enzymes-lipase protease and amylase), liver (produces bile), gall bladder (stores bile before releasing into duodenum), small intestine ( duodenum, ileum), large intestine (colon, rectum), anus
what is peristalsis
movement of matter through the digestive system
uses circular and longitudinal muscles of gut wall
digestion
mechanical digestion: chewing in mouth, churning in stomach
chemical: happens by action of enzymes in stomach and small intestine- duodenum
HCl in stomach provides acidic enviroment ideal for protease enzymes (pepsin) in stomach
bile neutralises acid and provides ideal alkaline environment for enzymes in small intestine, emulsifies fats increasing surface area for lipase enzymes to work on
absorption
process of moving digested food molecules from the small intestine into the blood/lymph- occurs mostly in ILIUM
the small intestine wall has villi which have microvilli that increase surface area for absorption
wall is only 1 cell thick: short distance for diffusion and active transport
network of capillaries transports digested food away
lacteal (small internal structure) transports digested fatty acids and glycerol into lymph
4 main blood groups
A- has A antigen on RBC, B antibody in plasma
B-has B antigen on RBC, A antibody in plasma
O- has neither A or B antigens on RBC, has A and B antibodies in plasma
AB- has both A and B antigens on RBC, has neither A or B antibodies in plasma
what is RhD
RBCs sometimes have another antigen, known as the RhD antigen-you can be RhD negative or positive
explain function of kidney
reabsorption of water to maintain water potential, nephron=functional unit of kidney
how do hormones work
travel in blood to target organs
what limits the length of a food chain
energy flow- at each trophic level energy is wasted e.g. not all matter can be consumed such as bone
pryamid of biomass
a graphical representation designed to show the biomass or bio productivity at each trophic level in a given ecosystem
processes that occur in the carbon cycle
respiration, combustion, decomposition, photosynthesis
process of nitrification
biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate:
NH3 to NO2- to NO3-
process of denitfication
the loss or removal of nitrogen or nitrogen compounds specifically : reduction of nitrates or nitrites commonly by bacteria (as in soil) that usually results in the escape of nitrogen into the air.
Nitrates are converted into nitrogen gas.
This process is disadvantageous for the soil and plants.
This is carried out by denitrifying bacteria.
Denitrifying bacteria do not need oxygen as they are anaerobic (therefore they thrive in waterlogged soil).
nitrogen fixation
Nitrogen gas is converted into nitrates by nitrogen fixing bacteria, which are aerobic
This process is quickened by the presence of oxygen and higher temperatures.
These bacteria can be found ‘free’ in the soil or in roots nodules found on the roots of plants such as peas, beans, and clover.
Within the root nodules the bacteria gain carbohydrates from the plant and the plant gains a source of nitrates in return
process of decomposition
Decomposers (some free-living bacteria and fungi) break down animal and plant proteins (from dead organisms) and nitrogenous waste products to release energy. As a result of decomposition nitrogen is released into the soil in the form of ammonium
nitrogen cycle stages
nitrogen fixation feeding excretion of nitrogenous waste decomposition nitrification uptake of nitrates denitrification
explain emulsification of fats during digestion
happens in lower intestine
bile releases from gall bladder causes the fat globules to be broken down into smaller lipid droplets which increase surface area for lipase to work on BUT THE LIPID SURFACE AREA FALLS
