Biology - B2

organisation

organisation in the body

cell - tissue - organs - organ system - organism

example of an organ system: mouth - oesophagus - stomach - intestines - anus

enzymes

biological catalysts - speed up breaking down/building substances in the body

only one kind of substrate can be broken down by one type of enzyme

what do the different types of enzymes do? (lipase, carbohydrase, amylase, protease)

lipase - breaks down fats into fatty acids + glycerol

carbohydrase - breaks down carbs into simple sugars

amylase - breaks down starch into simple sugars

protease - breaks down proteins into amino acids

where are enzymes found + made?

protease - small intestine + pancreas + stomach

carbohydrase - small intestine + pancreas + salivary glands

lipase - small intestine + pancreas

bile made in liver, stored in gallbladder, neutralises stomach acids + emulsifies fats

hydrochloric acid in stomach, allows protease to work + kills pathogens

REQUIRED PRACTICAL - food tests (starch, protein, lipids, sugar)

starch = iodine, orange - black

protein = biuret, blue - purple

lipids = make a sudan III solution, red floats on top

sugar = benedicts, heat, blue - green/orange/red

what do parts of lungs do (trachea, bronchi, alveoli) + how are lungs adapted?

trachea - airway that leads to the bronchi

bronchi - large tubes that connect your trachea + direct air to your right and left lungs

alveoli - air sacs at the end of bronchi, covered in capillaries for oxygen diffusion to bloodstream

lungs are adapted for fast diffusion:

* large surface area
* good blood supply
* thin membranes

heart + location of pacemaker

double circulatory system - right side pumps blood to lungs and left blood to rest of body

pacemaker (controls irregular heart rates) is placed in the RIGHT ATRIUM

what is the route of blood through heart?

VAVAVAVA:


1. vena cava
2. atrium - right
3. ventricle - right
4. artery - pulmonary (to the lungs)
5. vein - pulmonary (from the lungs)
6. atrium - left
7. ventricle - left
8. aorta (to the body)

what do the different types of blood vessels do? (arteries, veins, capillaries)

arteries - carry blood AWAY from the heart, have high pressure so need thicker walls

veins - carry blood TOWARDS the heart, lower pressure so need thinner walls + valves

capillaries - allows nutrients to leave blood and enter cells, need very thin walls for quicker diffusion

what do different blood cells do? (red, white, plasma, platelets)

blood is a tissue because it is a group of cells:

* red blood cells - carry oxygen around the body
* white blood cells - fight pathogens (lymphocytes + phagocytes)
* plasma - liquid part that carries hormones, glucose and carbon dioxide
* platelets - clot the blood

what is coronary heart disease + what are the treatments?

fatty material builds up inside the coronary arteries

this makes them narrow

less blood = less oxygen + glucose = stops respiration by heart cells, which leads to the heart not beating (heart attack)

ways to help:

* stents - wire mesh that widens the artery but needs surgery so open to complications
* statins - tablets that thin the blood

other heart problems + treatments

valves (between atrium + ventricle) may stop working or become leaky - means the heart cannot pump blood properly, replace with biological/mechanical valves

heart failure can require a heart transplant - sometimes artificial hearts are used to keep a person alive until a donor is found

what are health issues + what can they cause?

health is a state of physical and mental well-being

poor immune systems mean people are more likely to get infectious diseases

some viruses (HPV) can trigger cancers

immune interactions caused by a pathogen can cause allergies

poor physical health can lead to poor mental health

risk factors + what they can cause

risk factors are linked to an increased rate of disease

* poor diet/smoking/lack of exercise - cardiovascular disease
* obesity - type 2 diabetes
* alcohol - effects liver + brain function
* smoking - lung disease + lung cancer
* smoking/alcohol while pregnant - brain damage + premature birth
* carcinogens (gamma radiation) - cause cancers

what are the two types of cancer?

cancer is the uncontrolled growth of cells and cell division

there are two types:

* benign - tumours stay in one part of the body in a membrane and do not spread
* malignant - will spread in the blood to other parts of the body

what are the leaf tissues and what do they do?

a plant is made of organs: roots, stem, leaves, sometimes flowers

a leaf contains:

* epidermal tissues
* palisade layer - lots of chloroplasts
* spongy layer - allows gas exchange
* xylem + phloem - moves water + moves glucose
* guard cells + stomata - guard cells open and close the stomata to allow carbon dioxide to enter the plant and oxygen to leave
* also allows water to leave the plant

what is transpiration?

transpiration is the movement of water throughout a plant


1. root hair cells take in water from the soil
2. moves through the xylem to leaves for photosynthesis (a hollow cell strengthened by lignin)
3. some water is lost through the stomata of the plant
4. guard cells will close the stomata to stop water loss

ONE WAY

what is translocation?

translocation is the movement of dissolved sugars from the leaves to the rest of the plant

sugars are moved through the phloem - has elongated cells and each cell has small pores to allow the sugar through

BOTH WAYS