organisation Flashcards
(99 cards)
1
Q
What is a tissue? give example
A
A group of similar cells that have a particular function
muscular tissue, made up of muscle cell
2
Q
What is an organ? give example
A
Group of similar tissues that have a similar function
stomach, contains muscular tissue
3
Q
What is an organ system?
A
A group of organs working together to perform a particular function
4
Q
what is a catalyst?
A
A substance which increases the speed of a reaction without being changed or used up
5
Q
what does the digestive system do
A
break down large food molecules into smaller ones to absorb nutrients
6
Q
explain the lock and key model
A
- enzymes have SPECIFIC shape of active site to one type of molecule
- substrate BINDS to active site of enzyme as shape of active site and substrate are COMPLIMENTARY, forming enzyme-substrate complex
- chemical reaction occurs that BREAKS DOWN bonds between substrate, creating smaller molecules, products
- enzyme does not change
7
Q
what two conditions changes the rate of enzymes
A
Temperature and pH
8
Q
what happens to activity of enzyme as temperature increases
A
low: enzymes and substrates have low kinetic energy so fewer enzyme-substrate collisions
optimum: increased rate due to higher energy
too high: denature, active site changes shape, can no longer bind
9
Q
what happens to activity of enzyme as pH changes
A
has an optimum pH - if it becomes more acidic/alkaline, enzyme denatures
10
Q
what do enzymes do?
A
break down big molecules into smaller ones for digestion
11
Q
What enzyme converts starch and what does it convert them into?
A
Carbohydrase
simple sugars
12
Q
give an example of carbohydrase and where it is made
A
amylase, salivary, glands, pancreas, small intestine
13
Q
what converts proteins and what does it convert them into?
A
Protease
amino acids
14
Q
where is protease made?
A
Stomach (pepsin), pancreas, small intestine
15
Q
what converts lipids and what does it convert them into?
A
Lipase
one molecule of glycerol and three fatty acids
16
Q
where is lipase made?
A
Pancreas, small intestine
17
Q
how to prepare food for food test
A
- grind sample with distilled water in mortar and pestle to make paste
- transfer to beaker and stir with more distilled water to dissolve the chemicals
- filter to remove particles
18
Q
how to test for starch
A
- put 2cm cubed food solution in test tube
- add a few drops of iodine solution
if present: iodine turns browny-orange to bluey-black
19
Q
how to test for sugar
A
- put 2cm cubed food solution in test tube
- add 10 drops benedicts solution
- place test tube into water bath of hot water from kettle
- leave for 5 mins
if present: B’s solution turns blue to green to yellow to brick red depending on how much reducing sugar
20
Q
how to test for protein
A
- put 2cm cubed food solution in test tube
- add 2cm cubed biuret solution
if present: B solution turns blue to purple
21
Q
how to test for lipids
A
- put 2cm cubed UNFILTERED food solution in test tube
- add a 3 drops Sudan III stain solution and gently shake
if present: two layers form, top one bright red
22
Q
how to investigate affect of ph on amylase
A
- place 1 drop of iodine solution into each well of spotting tile. amylase enzyme catalyses the breakdown of starch, iodine turns blue black if starch is present
- fill three test tubes with 2cm cubed of: starch solution, amylase solution, and pH 5 buffer solution (controls pH)
- place test tubes in 30 degree water bath for 10 mins to allow them to reach correct temp
- combine three solutions into one solution and mix with stirring rod
- start stopwatch
- after 30 secs, transfer one drop of solution to a well on tile. iodine should turn blue black
- add solution to each tile at every 30 secs until iodine remains orange, when starch is no longer present, and record time of this
- repeat with different pH buffers
23
Q
limitations of investigating affect of ph on amylase
A
- only taking samples every 30 secs, result is approximate
- stopping when iodine stays orange is not always obvious, subjective
24
Q
what does small intestine and large intestine do
A
small
- produces the 3 enzymes
- absorbs food molecules from digestion into blood
large
- absorbs water from food
25
how is small intestine adapted to absorb products of digestion
- very long, 5m in humans: large SA
covered in villi to speed diffusion:
- large SA
- microvilli surround villi: even larger
- capillaries allow very good blood supply, bloodstream removes products rapidly
- thin membrane: shorter diffusion
26
what does the stomach do
- produces pepsin to digest proteins
- produces HCl to kill bacteria and provide optimum pH for pepsin
27
how and why does the body produce bile
produces in liver, stored in gall bladder, released into small intestine.
- neutralises HCl from stomach to allow enzymes in small intestine to work in less acidity
- emulsifies lipids, increasing SA to speed breakdown
28
Where does oxygen go when you breathe it in?
trachea - split into two bronchi - bronchioles - alveoli
29
how are we adapted for gas exchange
trachea - rings of cartilage to prevent collapse
breathing - brings oxygen to alveoli and takes away the co2, maintaining gradient
30
how are alveoli adapted for gas exchange and diffusion
- millions in lungs: huge SA
- thin walls: short diffusion path
- very good blood supply: rapidly removed to maintain gradient
31
What valves do?
Prevent blood flowing backwards
32
describe circulation in humans
double circulatory system:
blood passes through heart twice in one cycle
- to lungs by right side
- to body by left side
33
what does blood flow through to get to the right atria?
The vena cava
34
where is vena cava on diagram
LEFT side: diagram reverses
35
describe blood vessels that enter and leave heart
DO body - heart: vena cava
DO heart - lungs: pulmonary artery
O lungs - heart: pulmonary vein
O heart - body: aorta
36
explain how blood flows to the heart on the right side
- Enters right atria via vena cava
- Atria contracts, pushing blood into ventricles
- Ventricles contract, pushing blood into pulmonary artery
- valves stop backflow when ventricles contract
37
explain how blood flows through the heart on the left side
- Enters left atria via pulmonary vein
- Atria contract, pushing blood into left ventricle
- Ventricle contracts and leaves through the aorta
- valves stop backflow when ventricle contracts
38
why isnt a heart symmetrical
left has thicker muscular wall than right
left pumps blood around the entire body so needs to provide greater force, whereas right pumps only to lungs
39
what are coronary arteries
branch out of aorta and spread across the heart, to provide oxygen to muscle cells of heart for respiration for contraction
40
what is a pacemaker?
A group of cells in the right atrium that control the heart rate
41
what to do if pacemaker stops working correctly
artificial pacemaker - small electrical device that regulates heart rate
42
Features of an artery
- thick, muscular walls to withstand high pressure
- thicker elastic walls to regain shape in high pressure
43
Features of a capillary
- thin walls to shorten and speed diffusion
44
Features of veins
- thin wall as pressure is low
- valves to stop blood flowing in wrong direction
45
Name the four main things in blood
Red blood cell, white blood cell, platelets and plasma
46
what does RBC do and what are some features
carry oxygen to organs
- contains haemoglobin, which binds with oxygen in lungs to form oxyhaemoglobin, releases oxygen when RBC travels to organs
- no nucleus to allow more room for haemoglobin
- biconcave disc to increase SA
47
what does WBC do and what are some features
part of immune system to fight disease
- contain a nucleus, which has DNA that encodes WBC to do its know
48
what does plasma do
liquid that carries
- soluble products of digestion from small intestine to organs
- co2 (aerobic respiration) from organs to lungs to be exhales
- urea from liver to kidneys to be excreted
49
what do platelets do
fragments of cells that help blood to clot
50
uses of donated blood
- replace blood lost during injury
- provides platelets for clotting
- provides proteins eg antibodies
51
risks of donated blood
- ensure blood type is same otherwise immune system will reject it and patient could die
- disease transmitted via blood
52
what is coronary heart disease?
when layers of fat build up in coronary arteries, narrowing the artery.
partial: reduce flow
full: heart attack
53
What is a stent?
Tubes that inserted inside arteries that keep them open
54
Pros and cons of a stent
- blood can flow normally through artery
- only prevents narrowing in one region, other regions may block
- risk of blood clot near stent
55
what is a statin
Drugs that reduce level of bad cholesterol in blood, slowing rate of fat build up
56
pros and cons of statins
- reduced risk of coronary heart disease
- unwanted side effects eg liver problems
57
problems of poor valves
- dont fully open - heart has to pump harder, enlargens
- leaky, causing tiredness
58
solution to poor valves with pros and cons
mechanical valve
- lasts a lifetime
- anticlotting drugs must be taken
biological valve
- no drugs needed
- dont last long, may need replacing
59
what is heart faliure
when heart cannot pump enough blood around body
60
solution to heart failure with pros and cons
donated heart (and lungs)
- not enough donors for patients
- drugs needed to stop immune system rejecting heart
temporary artificial heart
- risk of clotting
- only temporary, not long term
61
risk of uncontrolled mitosis
tumours
62
benign vs malignant tumour
B: tumour contained in an area, a membrane, so do not invade other parts of body
M: cells can move into bloodstream & invade healthy tissue, forming secondary tumours, cancerous
63
causes of cancer
- uncontrolled mitosis (tumours)
- genetics eg breast
- lifestyle eg uv, smoking
- environment eg radon gas: ionising radiation - cells damaged - uncontrolled mitosis - lung cancer
64
how to find causes of disease
epidemiology - studying patterns of disease to determine its risk factors
causal mechanism - finding how risk factor leads to disease
65
how did scientists find cause of lung cancer
- scatter graph to see correlation and link between:
number of cigs per day & risk of developing lung cancer
years of smoking & risk of developing lung cancer
- causal mechanism to discover that chemicals in smoke is carcogenic (damages dna - cancer)
66
challenge of epidemiology and how to overcome
sampling - creates bias as sample may be unrepresentative of population
large, random samples taken
67
risk factors of cardiovascular disease
- diet: high fat increases bad cholesterol, increasing rate of fat build-up
high salt increases blood pressure, increasing risk
- smoking increases risk
- exercise decreases risk
68
risk factors linked to smoking
smoke is carcinogenic
- cardiovascular disease
- lung cancer
- lung disease eg emphysema
- miscarriage/premature if pregnant
69
risk factors linked to pregnancy
- smoking: miscarriage, prematurity
- drinking: fetal alcohol syndrome, learning difficulty
70
risks factors linked to alcohol
- fetal alcohol syndrome if pregnant
- liver cirrhosis and liver cancer
- addiction and memory loss
71
risks factors of to type 2 diabetes and what can it lead to
obesity
blindness/amputation
72
risk factors not linked to lifestyle
- environment eg radon: radioactive gas, risk of cancer
73
What is epiderman tissue/waxy cuticle
protective layer on top of leaf to prevent water loss via evaporation
74
what does the upper epidermis do?
It’s transparent, so that light can pass through it to the palisade layer
75
what does lower epidermis do
covered in stomata
- allow co2 to enter, oxygen to leave
- regulates water leaving/entering
surrounded by guard cells
- swell in high light intensity, stomata opens
- closes stomate in hot conditions to reduce water loss via transpiration
76
what does the palisade mesophyll layer do?
lots of chloroplasts - chlorophyll get lots of sunlight
77
what does spongy mesophyll do
full of air spaces
- allow co2 to diffuse from stomata to palisade cells
- allow oxygen to diffuse from palisade cells to stomata
78
what does the xylem do
transpiration STREAM
- transports water up plant (roots to stem and leaves) for photosynthesis
- transports dissolved mineral ions eg magnesium for chlorophyll
79
what does the phloem do
translocation: transports sugars from photosynthesis from leaves to rest of plant, for respiration or store as starch
80
what does the meristem do
at shoots and roots, contains stem cells which can become any cell
81
describe transpiration STREAM
evaporation from leaf surfaces
- evap occurs from cells within leaf
- vapour diffuses through spongy mesophyll
- exits via stomata
- xylem replaces water lost and absorbs more from root hair cells
82
importance of transpiration STREAM
- water for photosynthesis
- mineral ions eg magnesium for making chlorophyll
- cools leaf in warm weather
83
what affects rate of transpiration
- temp: hotter = faster evaporation
- humidity: low (less water vapour concentration) = faster evaporation
- wind: wind removes vapour = more vapour can evaporate
- light intensity: brighter = more stomata open
- more leaves
84
what are enzymes made out of
they are polymers so:
monomers of amino acids
85
why does reduction in breakdown of different molecules lead to weight loss
- less (food molecule) absorbed into blood
less glucose - less respiration, fat used for energy from respiration
less lipids - less fat stored in body
86
why is a placebo used
to allow a comparison to see effects of drug
87
blood in artery vs blood in vein
artery:
more glucose
more oxygen
less co2
less lactic acid
88
what do arteries carry
oxygenated blood away from heart, except pulmonary which carries deoxygenated
89
what affects number of stomata open
high light intensity: more open
90
what is epidermis in general
layers of cells lining upper and lower surface of leaf
91
why might one plant lose water faster than another plant
if seperate:
- windier/less humid/warmer/brighter
if in same room
- more leaves/bigger leaves/more stomata/greater SA of leaves/
92
when making a conclusion from data what measurements should you compare
percentages
93
how do guard cells open stomata
- in high water availability, water moves into guard cell via osmosis
- inner wall is less flexible than outer wall as it is thicker, so it swells unevenly, causing stomata to open
94
how do ions moving into guard cells cause them to open
- more ions = decrease concentration of water
- water moves in via osmosis
- inner wall is less flexible than outer wall as it is thicker, meaning it swells unevenly, causing stomata to open
95
why is too many stomata bad
- more water lost
- plant will wilt (collapses as cells are not full of water, so cell wall can no longer support the plant
96
why are there fewer stomata in high co2 conc
more co2 so not as many stomata needed to obtain amount of co2
97
what actually is stomata
the pore (gap) that controls water loss (vapour) and gas exchange
98
why are stomata on lower leaf
less water loss:
less light intensity, less photosynthesis, less co2 needed, less stomata have to be open, less water loss
99
how does increased muscle mass affect athlete
faster and stronger, as larger muscle mass for stronger contractions
