- Created by: abbiedye
- Created on: 20-06-18 10:20
What are cell organisations?
- Large multicellular organisms are made up of organ systems
- Similar cells make up tissues
- Tissues make up organs
- Organs make up organ systems
What type of cells are organised into tissues?
Tissue - group of similar cells that work together to carry out a particular function
- Muscular tissue - contracts to move whatever its attached to
- Glandular tissue - make and secrete chemicals like enzymes and hormones
- Epithelial tissue - cover some parts of the body (inside the gut)
What types of tissues are organised into organs?
Organ - group of different tissues that work together to perform a certain function
- Muscular tissue - moves the stomach wall to churn up food
- Glandular tissue - makes digestive juices to digest food
- Epithelial tissue - covers the outiside and inside of the stomach
What types of organs are organised into organ syst
Organ systems - group of organs working together to perform a function
- Glands - (pancreas and salivary glands) - produce digestive juices
- Stomach and small intestine - digest food
- Liver - produces bile
- Small intestine - absorbs soluble food molecules
- Large intestine - absorbs water from undigested food - faeces
Organ systems - organsims
What are enzymes?
- Enzymes are large proteins - chains of amino acids
- They speed up reactions inside living things by acting as catalysts
How do enzymes catalyse reactions?
- enzymes have special shapes so they can catalyse reactions
- enzymes only catalyse one specific reaction - unique shape
- 'lock and key'
Why do enzymes need the right temperature and pH?
- too hot - 45 degrees - bonds holding the enzyme together break - change enzymes active site - 45 degrees = denatured
- too high / low pH - intefers with bonds holding the enzyme together - changes the shape of the active site - denatures
Explain digestive enzymes
- starch, proteins and fats are big molecules
- they're too big to pass through the walls of the digestive system
- so digestive enzymes break these big molecules down into smaller ones
- these smaller, soluble molecules can easily be absorbed into the bloodstream
What are carbohydrates converted into?
- Carbohydrases convert carbohydrates into simple sugars
- Amylase is a carbohydrase, it breaks down starch
- Made in - salivary glands, the pancreas, the small intestine
What are proteins converted into?
- Proteases convert proteins into Amino Acids
- Protease = enzyme
- Made in - the stomach (called pepsin), the pancreas, the small intestine
What are lipids converted into?
- Lipases convert lipids into glycerol and fatty acids
- Lipase = enzyme
- Made in - the pancreas, the small intestine
How does bile neutralise stomach acid?
- Produced in liver - stored in gall bladder - released into acidic small intestine
- Bile = alkaline - it neutralises and makes conditions alkaline and the enzymes work best in alkaline conditions
Where are the different enzymes produced?
- Salivary glands - amylase enzyme in saiva
- Stomach - pummels food, protease enzyme (pepsin), acid - kill bacteria, right pH for protease
- Liver - produces bile - neutralises stomach acids + emulsifies fats
- Gall bladder - where bile is stored
- Pancreas - produces protease, amylase and lipase - released in small intestine
- Large intestine - excess water from food absorbed
- Small intestine - protease, amylase and lipase - complete digestion
- Rectum - faeces
What are the different food tests?
- Benedicts test for sugars - turns from blue to green, yellow or brick-red
- Iodine solution for starch - turns from browny-orange to black or blue-black
- Biuret test for proteins - turns from blue to pink or purple
- Sudan III for lipids - top layer turns bright red
How do the lungs work
- Air breathed in goes through the trachea - splits into two tubes called bronchi, one going to each lung
- The bronchi split into bronchioles which end at small bags called alveoli
How do the alveoli carry out gas exchange?
- Blood passing next to the alveoli contains lots of carbon dioxide and very little oxygen
- Oxygen diffuses out of the alveolus (high concentration) into the blood (low concentration) alveolus
- Carbon dioxide diffuses out of the blood into the alveolus
How does the heart's double circulatory system wor
- Two circuits
- Right ventricle - deoxygenated blood to the lungs to take in oxygen - then returns to the heart
- Left ventricle - pumps oxygenated blood around all other organs - the blood gives up its oxygen - deoxygenated blood returns to the heart
How does the heart pump blood around the body?
1. Blood flows into two atria from the vena cava and pulmonary vein
2. Atria contract - blood into ventricles
3. Ventricles contract - blood into pulmonary artery and aorta - out of the heart
4. Blood flows to organs through arteries and returns through veins
5. Atria fill again and cycle starts over
Circulatory system - The heart
- The heart is an organ with four chambers
- It is used to pump blood around the body
- The valves in the heart stop blood flowing backwards
- The heart also needs its own supply of oxygenated blood
Circulatory system -Blood vessels
- Arteries carry blood under pressure (carry the blood away from the heart)
- Arteries branch into capillaries which carry blood close to every cell
- Capillaries join up to form veins that take blood back to the heart
How do arteries, capillaries and veins work?
- Arteries - the heart pumps blood at a high pressure - artery walls are strong and elastic
- Capillaries - arteries branch into capillaries - close to every cell to exchange surfaces
- Veins - capillaries join up to form veins - blood is lower pressure - back to heart
Circulatory system - Blood
- Red blood cells carry oxygen
- White blood cells defend against infection
- Platelets help blood clot
- Plasma is the liquid that carries everything in blood
What is coronary heart disease and what are stents
- Coronary heart disease - coronary arteries get blocked by layers of fatty material causing restricted blood flow and lack of oxygen to the heart
- Stents - tubes inserted inside arteries - keep them open - they are effective (long time) but they can cause infection due to blood clots (thrombosis)
What are statins?
- Statins reduce cholesterol (essential lipid) - excess = health problems / fatty deposit
-reducing strokes, heart disease + heart attacks -increase 'good' cholesterol -prevent other diseases
-long-term drug (forgotten)
-negative (serious) side effects / kidney damage -effects aren't instant
What methods can be used to prevent heart disease?
- Artificial heart - heart failure - ca pump blood - don't work as well - drugs to thin blood - electric motor could fail - surgery - infection and bleeding
- Biological or mechanical valves - replace faulty valves - less drastic procedure - major surgery - blood clots
- Artificial blood - emergency - blood substitute - 'saline' -safe (no air bubbles) - gives time for patient to produce new blood cells
What factors can affect your health?
Diseases interact - problems with immune system - communicable diseases - cancer + viruses and mental health + physical health problems
Factors - diet, stress, life situation
What are the factors of non-communicable diseases?
Increased chance - lifestyle (developed areas), environment, interacting with others
Direct causes - smoking (lungs and heart), obesity (diabetes), too much alcohol (liver), exposure to radiation (cancer)
Non-communicable diseases - costly - human lives (shorter lifespan) - financial (NHS research)
What is cancer?
Benign - stays in one place - isn't cancerous Malignant - break off into bloodstream - dangerous
Risk factor - smoking, obesity, UV exposure, viral infection and genetics
How are plant cells organised?
- Waxy cuticle - reduce water loss
- Epidermal tissue - transparent = light ca go through
- Palisade mesophyll tissue, spongy mesophyll tissue and epidermal tissue- gas exchange
- stomata and guard cells - respond to enironment changes
Xylem and phloem - deliver water and nutrients
Transpiration and Translocation
Translocation - Ploem = food (dissolved sugars) and xylem = water and minerals
Transpiration - caused by the evaporation and diffusion of water from a plant's surface - drawn up from roots to leaves - constant transpiration rate / stream
Transpiration stream = roots to xylem to leaves
What affects transpiration rate?
Light intensity - brighter = greater rate Temperature - warmer = greater rate Air flow - stronger wind = greater rate Humidity - drier = greater rate
Guard cells - adapted for gas exchange + water loss control - plant has lots of water - stomata open - gases exchanged for photosynthesis - short of water - stomata close - more stomata on undersides - cooler - less water lost