Biology Unit 1

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  • Created by: Sopha8
  • Created on: 13-05-14 20:32
What are some risk factors for cancer and coronary heart disease?
Cancer- smoking, exposure to sunlight and excessive alcohol consumption CHD- poor dies (high saturated fat/salt), lack of exercise and smoking
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What is a pathogen? How do they enter the body?
An organism that causes diease. 1)gas exchange system-breathed in, get past cilia, 2)skin- before scab forms, 3)digestive system-often killed by stomach acid but some get through
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How do pathogens cuase diease?
1) produce toxins, 2) cell damage- rupture cells to release nutrients and break down to use themself,/ replicating inside cell
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What is an antigen?
Molecules (often proteins) found on the surface of cells, identifies a pathogen as forgein to activate primary immune respone
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Explain the 4 stages of the immune response
1) phagocytosis, 2) T-cell activation, 3) B-cell activation and plasma cell production 4) antibody production
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What is the primary and secondary response in the immune respone?
primary- slow as producing antibodies, symtoms show, memory cells produced, secondary response-same pathogen, memory cells divide, quicker so not symptoms
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How do vaccines work?
contain antigens (free or attached to dead/attenuated pathogen) produce memory cells to become immune. orally could be broken down by enzymes in gut.
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What is antigenic variation?
Different antigens are formed due to changes in the genes of a pathogen, memory cells wont produce antibodies as they don't recognoise antigen
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Explain the ethics behind monoclonal antibodies
Manufactured to bind to antigen you want, produced from single group of similar B-cells, animal rights
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What are the monomers of carbs and proteins? what are they made from?
carbs-monosaccharides, C,H and O, proteins-amino acids, C,H,O and N
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Decribe the role of the 7 parts of the digestive system
1) buccal cavity, 2) oesophagus, 3) stomach, 4) small intestine, 5) large interstine, 6) rectum and 7) pancreas
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What are proteins made of?
one or more polypeptide (more than 2 amino acids) joined by peptide bonds by condensation reaction
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What are 3 monosaccharides and what 3 disaccharides do they form in condensation reaction?
1) glucose, 2) galactose, 3) fructose, 1) maltose-gl +gl, 2) lactose (gl+ga) and 3)sucrose (gl+ f)
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What reaction breaks down polysaccharides?
hydrolysis, add H2O
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Explain the test for starch
add iodine dissolved in potassium iodide, yes strach= from brown/orange to dark blue/black
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In benedicts test, what colour shows sugar present?
red, reducing after 1st heat, non-reducing after heat with hydrochloric acid then neutralise with sodium hydrogen carbonate
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What is the test for proteins?
Biuret test- sodium hydroxide then copper sulphate solution, yes protein= turns purple
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Explain the induced fit model of enzymes
active site which has specific shape to complement subtrate molecule so they can bind and form enzyme-subrate complex, changes shape slightly to complete the fit
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What are the 3 factors affecting enzyme activity?
1) temperature- high=more collisions, too high=tertiary structure lost, no E-S C formed, 2)Ph-above/below optimum=H+ or OH- disrupt bonds, 3) subtrate concentration- higher=faster, saturation point
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What are the 2 types of inhibitors?
molecules, 1)competitve-compete for acitve site, 2) non-competitive-not active site, change shape of active site, no E-S C can be formed
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What is a lysosome?
organelle surronded by membrane, contains digestive enzymes-digest invading cells or break down worn out components
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How do you work out the length of a specimen?
mag=image length/ specimen length so specimen length= image length/mag
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In cell fractionation why are the cells homogenised?
break up cells to release organelles, vibrating or grinding in blender
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Explain the propertise of a plasma membrane
1 controls what goes in/out-different proteins allow passage of certain substamces 2 barrier against water-soluble- hydrophobic tail hydrophilic head=bilayer 3 communicstion-receptor proteins 4 cell recognition-glycoprotein/glycolipid 5 fluid-c
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If a cell is placed in a solution with a higher water potential what will happen?
water moves into cell by osmosis- swells, HYPOTONIC
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How do chloera lead to diarrohea?
bacteria produces toxins, causes chloride protein channels to open, chloride ions lower water potential in lumen, water moves out blood by osmosis
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What does an ORS contain?
salts (sodium ions and chloride ions) and sugars (glucose and sucrose)
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Journey of air into the lungs
1) trachea 2) bronchi 3) bronchoiles 4) alveoli 5) gas exchange into caplillaries
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What happens during inspiration and expiration?
inspiration- inter and dia contract, rib up and out= increase volume, decrease pressure, active process expiration-inter and dia relax, rib down=volume decreased, pressure increase, force air out
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What 3 things affect rate of diffusion?
1) thickness of exchange surface, 2) surface area, 3) concentration gradient
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How do you measure lung function?
pulmonary ventiliation (volume air tacken in, one min)=tidal volume (volume air each breath) X ventialtion rate (breaths per min)
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Flow of blood joureny- in order starting at vena cave
vena cava-R atrium-tricuspid valve-R ventricle-seimluna valve-pulmonary artery-pulomanary veins-lungs-L artium-bicuspid valve-L ventricle-semilunar valve-aorta-through body-vena cava
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Explain why the heart is myogenic
myogenic=contractions from muscle itself, SAN-AVN- Bundle of His-Purkyne fibres
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What is the volume of blood pumped by the heart in 1 min called? how do you calculate it?
cariac output, CO=stroke volume (blood pumped during each heartbeat) X heart rate (beats per min)
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What is an atheroma and what can it lead to?
biuld up of fatty material forming hard plaque in wall of artery, lead to-aneurysm, thrombosis therefore increase risk of myocardinal infarction
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Card 2


What is a pathogen? How do they enter the body?


An organism that causes diease. 1)gas exchange system-breathed in, get past cilia, 2)skin- before scab forms, 3)digestive system-often killed by stomach acid but some get through

Card 3


How do pathogens cuase diease?


Preview of the front of card 3

Card 4


What is an antigen?


Preview of the front of card 4

Card 5


Explain the 4 stages of the immune response


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