bio paper 1 - worst questions Flashcards
(22 cards)
evaluate using a mechanical valve replacement vs a biological valve replacement
mechanical and biological: 1 pro, 2 cons
mechanical : less people die of heart-related causes, can cause excessive bleeding, some patients can here the heart valve opening and closing
biological: no addition medication required, likely to be rejected, ethical isssues with using animal tissue
explain how diabetes can cause the body cells to lose more water (3)
- blood is more concentrated than solution in cells
- water moves out of cells by osmosis
- water moves through partially permeable membrane
how is the small intestine adapted for efficient absorption (4)
(it breaks down food to absorb water and nutrients)
with explanations for all of them
- villi provide large surface area
- capillaries only 1 cell thick so short diffusion rate
- good blood supply to maintain concentration gradient
- many mitochondria for aerobic respiration for active transport
explain how pancreatic cancer may cause a person to lose weight (3)
(the pancrease digests enzymes and secretes hormones)
with explanations for all of them
- reduced enzyme production so food not broken down properly
- less glucose in blood so less glucose for respiration so fat is used up instead for respiration
- less amino acids in blood so no amino acids to make proteins for repair
explain how monoclonal antibodies work to treat pancreatic cancer (3)
- monoclonal antibodies get attached to drug
- antibody will target antigens on cancer cells
- drug will bind to cancer cells, destroying them
describe how energy for photosynthesis is gained by plants (2)
through light that is absorbed by chlorophyll which is in the chloroplasts
explain how lungs are adapted for efficient gas exchange by diffusion (4)
- aveoli provide large surface area
- capillaries are 1 cell thick so short diffusion path for oxygen and carbon D
- breathing maintains the concentration gradient of oxygen and carbon D
- good blood supply that removes oxygenated blood quickly , being carbon D to lungs quickly
describe the 3 stages in the cell cycle
- DNA, chromosomes and sub-cellular structures duplicate
- one set of chromosomes pulled to each end of the cell
- cytoplasm and cell membrane split into 2 cells
explain the lock and key theory of enzyme action (3)
- enzymes bind to substrate as they’re complementary shapes
- substrates broken down into their products
- products are released and enzyme is unchanged
explain 2 reasons for yellow leaves and stunted growth
1.lack of magnesium ions - chlorophyll is made up of magnesium, without it insufficient amounts of chlorophyll are made leading to chlorosis (yellow leaves) without glucose formed from photosynthesis plant stops growing
2.infection from pathogen - leaves get discoloured so rate of photosynthesis lowers and less glucose made, and less proteins for growth
effects of liver failure (3)
with explanations for all of them
- no bile made in liver, so may lose weight
- lactic acid not broken down, so causes muscle pain/fatigue
- other toxins are not broken down, like alcohol, so body will be poisoned
describe how clinical trials should be carried out (6)
- given to healthy volunteers - at a very low dosage and checked for any side effects
- given to patients with the disease - to test for optimum dosage, done in a double blind test
- it is put in a large trial for a long duration
what are two ways skin prevents pathogens entering
- acts as a physical barrier against them
- produces antimicrobial secretions that kill bacteria
how to prevent mosquitoes transmitting malaria, explain how
use mosquito nets
prevents them from biting human and transmitting the disease
what are the 4 parts of the blood and what do they do
plasma - transports nutrients and hormones
white blood cells - carries oxygen using haemoglobin
red blood cells - defends against infections e.g. producing antitoxins, phagocytes, lymphocytes
platelets - helps with blood clotting
give two examples of metabolic reactions that will happen in a runner
-breakdown of glucose in respiration to release energy
-formation of amino acids from glucose and nitrates
how are monoclonal antibodies produced (5)
mouse injected with antigen
lymphoytes/ antibodies are produced in mouse
lymphocytes harvested and are fused with tumour cells, fast at reproducing creating hybridoma cell
these divide and produce identical antibodies
antibodies collected for treatment and diagnosis
how are mAbs used for diagnosis and treatment
bind to cancer cells, allowing detection
deliver toxic drugs directly to cancer cells
helps destroy cancer cells while minimising damage to normal cells
movement of substances done by xylem and phloem change between night and day explain the differences (3)
more transpiration (xylem) during day because of higher temps
stomata closed at night to reduce water loss
less translocation (phloem) during night because of lower photosynthesis rates
4 uses for glucose in the plant
used in respiration to release energy
converted into starch for storage
used to make cellulose for cell walls
used with nitrates to make amino acids/proteins for growth
one example for physical, chemical, and mechanical defences
bark
poisons
thorns
what do statins and stents do
statins lower blood choleterol to reduce fatty deposits in arteries
stent are inserted into arteries to keep them open for better blood flow
