B2 - Cell Organisation

moltose/maltease need to know?

How do cells become specialised?

differentiation

What are organ systems made of?

organs

What are organs made of?

tissue

What are tissues made of?

specialised cells

Def: organ system

a group of organs working together to carry out a specific function

Eg: organ system

digestive system

Def: organ

group of tissues working together to carry out a specific function

Eg: organ

heart

Def: tissue

a group of similar cells working together to carry out a specific function

What are the 3 types of tissue?

muscular, glandular, epithelial

What is the function of muscular tissue?

allows movement through contracting

What is the function of glandular tissue?

makes and secretes hormones and enzymes

What is the function of epithelial tissue?

to cover parts of the body e.g inside of gut

Def: enzyme

biological catalyst

How do enzymes work?

lock and key theory

What is the optimum temperature for enzymes?

40°C

What is the (general) optimum pH for enzymes?

pH 7

What happens if an enzyme is exposed to too high temps or high/low pH

denatures

Def: denature

active site of an enzyme changes shape and substrate no longer fits

RQ: enzyme activity

amylase breakdown

Independent variable of RQ: enzyme activity

pH of buffer solution

Dependent variable of RQ: enzyme activity

rate of amylase breakdown

How is rate of amylase breakdown measured?

how quickly iodine solution turns blue-black

What are the control variable of RQ: enzyme activity

concentration of amylase solution, volume of amylase solution, temperature of solution

Formula: rate of reaction

1000/ time

What are the 3 digestive enzymes?

amylase, protease, lipase

What is the process of amylase?

starch → simple sugars

Where is amylase made?

salivary glands, pancreas, small intestine

What is the process of protease?

proteins → amino acids

Where is protease made?

stomach, pancreas, small intestine

What is protease in the stomach called?

pepsin

What is the process of lipase?

lipids → glycerol and fatty acids

Where is lipase made?

pancreas, small intestine

What are the functions of bile?

neutralises stomach’s hydrochloric acid so as not to denature small intestine enzymes and emulsifies fat

Where is bile made?

liver

Where is bile stored?

gall bladder

Why are large food molecules broken down?

so they can be absorbed into the bloodstream

What is the food test for sugar?

Benedict’s solution - after preparing it in a water bath add some to sample. The more red it is, the higher sugar content.

What is the food test for starch?

Iodine - add iodine to sample. If it turns blue/black starch is present

What is the food test for proteins?

Biuret test - add Biuret’s solution. If proteins are present the solution will turn from blue to pink/purple

What is the food test for lipids?

Sudan III solution - add to solution. If lipids are present the solution will separate into 2 layers with the the top layer a bright red.

How does air get to the alveoli?

trachea → bronchi → bronchioles → alveoli

How is has exchanged in the lungs?

high concentration of O₂ in the alveoli it diffuses into the bloodstream to be carried around the body

high concentration of CO₂ in the blood diffuses into alveoli to be exhaled

What are the features of alveoli that help with its function?

thin walls

large surface area

lots of capillaries

Why are thin walls an adaptation of alveoli?

easy diffusion

Why is a large surface area an adaptation of alveoli?

more substances exchanged

Why is lots of capillaries an adaptation of alveoli?

easy access to bloodstream

What does the right ventricle do?

pumps deoxygenated blood to the lungs

What does the left ventricle do?

pumps oxygenated blood from the heart around the body

Def: heart valves

one way valves that keep blood flowing in the right direction

How does the heart work?

1. blood flows into the atria then ventricles
2. ventricles contracts
3. blood moves out of the heart
4. blood flows around the body
5. repeat

Where does blood enter the right atrium?

vena cava

Where does blood exit the right ventricle?

pulmonary artery

Where does blood enter the left atrium?

pulmonary vein

Where does blood exit the left ventricle?

aorta

What gives the heart its blood supply?

coronary arteries

What controls the contractions of the heart?

pacemaker

How does the pacemaker control the heart?

sends out electrical impulse

Where is the pacemaker found in the heart?

right atrium wall

What are the 3 types of blood vessel?

* arteries
* capillaries
* veins

Def: arteries

* carries oxygenated blood
* at high pressure
* small lumen
* thick walls

Def: capillaries

* exchanges substances with cells
* very small
* thin cell walls
* permeable walls

Def: veins

* carries deoxygenated blood
* at low pressure
* large lumen
* valves

Rate of blood flow =

volume of blood / number of minutes

What are the components of blood?

* red blood cells
* white blood cells
* platelets
* plasma

Def: red blood cells

carry oxygen around the body

What the adaptations of a red blood cell?

* biconcave shape
* don’t have a nucleus
* contain haemoglobin

Why do red blood cells have a biconcave shape?

large surface area for absorbing oxygen

Why do red blood cells not have a nucleus?

to have more space for oxygen

Def: haemoglobin

a red pigment that binds to oxygen

Def:

cells that defend against infection

How do white blood prevent infection?

* phagocytosis
* produce antibodies
* produce antitoxins

Def: phagosytosis

phagocytes surround a bacterium and engulf it, destroy it with enzymes

Def: antibodies

proteins produced by a B lymphocyte that attack foreign bodies unique to each pathogen

Def: antigen

flags foreign bodies to the immune system

How do antibodies work?

destroy cells that are marked by antigens, antibodies are also carried round the blood stream to destroy any similar cells

How do anti-toxins work?

neutralise toxins

Def: platelets

small fragments of cells that clot wounds

What are the consequences of a lack of platelets?

excessive bleeding and bruising

Def: plasma

liquid that carries other components of the blood

Def: cardiovascular disease

disease of the heart or blood vessels

Def: Coronary heart disease

when coronary arteries are blocked by layers of fatty build up

What can CHD lead to?

heart attack

How is CHD treated?

* stents


* statins

Def: stents

tubes placed inside arteries allowing blood to pass through

What are the pros of stents?

* lower risk of heart attack
* long lasting
* quick recovery time

\

What are the cons of stents?

* risk of surgical complications
* risk of thrombosis (clotting) post surgery

Def: HDL cholesterol

‘good’ cholesterol

Def: LDL cholesterol

‘bad’ cholesterol

Def: statins

a drug that lowers LDL cholesterol levels → less build up in coronary arteries

What are the pros of statins?

* lowers risk of heart attack
* increases levels of HDL cholesterol
* lowers levels of LDL cholesterol
* some studies suggest statins prevent other diseases

What are the cons of statins?

* long term drug
* side effects (e.g kidney failure)
* take time to take effect

What are the pros of an artificial heart?

* can enable a wait for a donor
* less likely to be rejected

What are the cons of an artificial heart?

* major surgery
* artificial hearts don’t work as well as real hearts

What are the pros of valve replacement surgery?

* less drastic procedure
* can be artificial

What are the cons of valve replacement surgery?

* biological valves can be rejected
* major surgery
* can cause clots

Def: artificial blood

a substitute for blood to give time for patient to produce blood of their own or get a transfusion

Def: communicable diseases

can spread from person to person

Def: non-communicable diseases

cannot spread between people

Def: cancer

uncontrolled cell growth and division