B2 Flashcards
What are cells?
Cells are the basic building blocks of all living organisms.
What are tissues?
A tissue is a group of cells with a similar structure and function.
What are organs?
Organs are aggregations of tissues performing specific functions.
What are organ systems?
Organs are organised into organ systems, which work together to form organisms.
What are 2 examples of tissues?
- Muscular tissue - contracts to move whatever it’s attached to. 2. Glandular tissue - secretes chemicals like enzymes and hormones.
What is an example of an organ?
The stomach which is made of muscular tissue etc.
What is an example of an organ system?
The digestive system
What is a catalyst?
A catalyst speeds up the rate of the reaction by giving the energy another path to travel to. It does not use up any reactants.
What is the aim of the digestive system?
To digest and absorb food
How does the lock and key method work for enzymes?
There is a specific substrate which fits the specific active site.
What happens to an enzyme when you increase the temperature too much?
Some of the bonds holding the enzyme together break so the active site changes so the substrate doesn’t fit. It is denatured.
What happens to an enzyme when you change the pH too much?
Some of the bonds holding the enzyme together break so the active site changes so the substrate doesn’t fit. It is denatured.
Where is amylase produced? (3)
- Small intestine. 2. Pancreas. 3. Salivary glands
Where is lipase produced? (2)
- Small intestine. 2. Pancreas
Where is protease produced? (3)
- Small intestine. 2. Pancreas. 3. Stomach
What does amylase break down and into what?
Breaks down starch into maltose and other sugars.
What does carbohydrase break down and into what?
Breaks down carbohydrates into simple sugars
What does lipase break down and into what?
Breaks down lipid (fats and oils) into fatty acids and glycerol
What does protease break down and into what?
Breaks down proteins into amino acids.
Where is bile made and stored?
Made in the liver and stored in the gallbladder.
What does bile do?
It is alkaline to neutralise hydrochloric acid from the stomach. It also emulsifies fat to form small droplets which increases the surface area.
How can bile increase fat breakdown?
The alkaline conditions and large surface area increase the rate of fat breakdown by lipase.
Required practical activity 5: investigate the effect of pH on the rate of reaction of amylase enzyme. (6)
- Put a drop of iodine solution into every spotting tile. 2. Heat water until 35 degrees over bunsen burner. 3.Use a syringe to add 1cm cubed of amylase solution and buffer solution with pH 5 and wait 5 mins. 4. Use a different syringe to add 5cm cubed of starch to beaker and mix and start clock. 5. Every 30 seconds add this to spotted tile. 6. When it stays orangey brown starch is no longer present.
What’s the test for sugars and how does it work? (4)
Benedict’s test. 1. Transfer 5cm cubed of food sample into a test tube. 2. Set water bath to 75 degrees. 3. Add Benedict’s solution using a pipette and add to water bath and leave for 5 mins. 4. If protein is present, it should change from blue to green or yellow or red (depending on how much sugar).
What’s the test for lipids and how does it work? (3)
Sudan III test. 1. Transfer 5cm cubed of food sample into a test tube. 2. Use a pipette to add 3 drops of sudan III stain solution and shake. 3. If lipids are present, top layer will be red.
What’s the test for proteins and how does it work? (3)
Biuret test. 1. Add 2cm cubed of food into test tube. 2. Add 2cm cubed of biuret solution and shake. 3. If protein is present it will go from blue to purple.
What’s the test for starch and how does it work? (3)
Iodine solution. 1. Transfer 5cm cubed of food into a test tube. 2. Add iodine solution and mix. 3. If starch is present, it will turn from orangey brown to blacky blue.
What is the journey of when air enters the body?
First it goes through the trachea. Second it splits into either bronchus (going to each lung). The bronchi are split into bronchioles and then small air sacs called alveoli where gas exchange happens.
Explain how gas exchange occurs.
- Oxygen diffuses into the blood and carbon dioxide diffuses out of the blood (and leaves.) 2. When the blood reaches body cells, oxygen is released from the red blood cells and diffuses into the body cells.
What are the adaptations of the lungs?
- Large surface area to volume ratio (alveoli). 2. Short diffusion path (as one cell thick). 3. Moist walls. 4. Good blood supply.
Why is the heart a double circulatory system?
The right ventricle pumps blood to the lungs where gas exchange takes place. The left ventricle pumps blood around the rest of the body.
Why is the left ventricle thicker than the right?
It needs to pump the blood a bigger distance (all around the body) instead of just to the lungs.
What is the heart and what is it made of?
An organ made of muscular tissue.
What does the heart have which prevents blood backflow?
Valves
What are the 4 chambers of the heart from top left to bottom left or top right to bottom right?
Right atrium. Right ventricle. Left atrium. Left ventricle.
How does the heart pump blood? (4)
- Deoxygenated blood enters through the vena cava and goes to the right atrium. 2. It flows through the right ventricle and leaves through the pulmonary artery to go to the lungs. 3. Oxygenated blood arrives back at the heart through the pulmonary vein. 4. It goes through the left atrium and left ventricle and leaves via the aorta (to go to the rest of the body).
What is a (natural) pacemaker?
The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker.
What does an artificial pacemaker do?
Artificial pacemakers are electrical devices used to correct irregularities in the heart rate.
Info about arteries (4)
- Go away from heart. 2. Strong walls to withstand high pressure. 3. Thick walls and smaller lumen. 4. Walls have layers of muscles which are elastic.
Info about veins (4)
- Goes towards heart. 2. Thinner walls as less pressure. 3. Bigger lumen to help blood flow. 4. Valves to keep blood flowing in the right direction.
Info about capillaries (3)
- Supply food and oxygen and removes waste like CO2. 2. One cell thick walls to maximise diffusion. 3. Permeable walls for diffusion.
What does a red blood cell do?
Carry oxygen.
How is a red blood cell adapted to do this? (3)
- Biconcave shape so large surface area to volume ratio. 2. No nucleus so more room for oxygen. 3. Haemoglobin binds to oxygen.
What does a white blood cell do? (3)
- Phagocytosis. 2. Release antitoxins and antibodies. 3. Nucleus.
What do platelets do?
Help blood clot.
What does plasma do?
Pale straw coloured liquid which carried everything including: red and white blood cells; platelets; nutrients like glucose; urea; carbon dioxide and more.
What is coronary heart disease?
Layers of fatty material build up inside the coronary arteries, narrowing them. This reduces the flow of blood through the coronary arteries, resulting in a lack of oxygen for the heart muscle.
What are 2 methods to help CHD?
Stents are used to keep the coronary arteries open. Statins are widely used to reduce blood cholesterol levels which slows down the rate of fatty material deposit.
What are advantages and disadvantages of stents?
Advantages: effective for a long time; lowers risk of heart attack and recovery time is quick. Disadvantages include: risk of complications from surgery; risk of infection; risk of blood clot near stent and if lifestyle doesn’t change then cholesterol can still build up over.
What are some advantages and disadvantages of statins?
Advantages: lowers risk of CHD and heart attacks etc; increase beneficial cholesterol and may help other diseases. Disadvantages: long term drug which needs taken regularly (so person could forget); some negative side effects and needs time to kick.
How can valves in the heart be weakened? (3)
- Heart attacks. 2. Infection. 3. Old age.
About faulty heart valves?
In some people heart valves may become faulty, preventing the valve from opening fully, or the heart valve might develop a leak
How can faulty heart valves be fixed?
Faulty heart valves can be replaced using biological or mechanical valves
What is health?
Health is the state of physical and mental well-being.
What is a communicable disease?
Can be spread from person to person or between animals.
What is a non - communicable disease?
Cannot be spread by people.
What are some factors which affect your health? (3)
- Disease. 2. Stress. 3. Diet.
What are some risk factors for type 2 diabetes? (3)
- Obesity. 2. Age. 3. Family history
What are some risk factors for cancer?
- Smoking. 2. Obesity. 3. Too much sunlight. 4. Alcohol / drugs
What is cancer caused by?
Uncontrolled growth and division of cells.
What is a benign tumour?
Benign tumours are growths of abnormal cells which are contained in one area, usually within a membrane. They do not invade other parts of the body.
What is a malignant tumour?
Malignant tumour cells are cancers. They invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours.
Risk factors of cancer? (4)
- Smoking. 2. UV exposure. 3. Obesity. 4. Viral infection
How is a leaf made up from the top to bottom? (7)
- Waxy cuticle - to reduce water loss. 2. Epidermal tissue - transparent to allow light through. 3. Palisade mesophyll tissue - lots of chloroplasts to get the most light. 4. Xylem and phloem - bring nutrients and water and dispose of glucose. 5. Spongy mesophyll - air gaps for more diffusion. 6. Lower epidermis. 7. Stomata (controlled by guard cells) lets CO2 diffuse.
How is the root hair cell adapted for diffusion? (3)
- Large surface area to volume ratio. 2. Thin cell walls for short diffusion path. 3. No chloroplasts to allow them to focus on their function instead of gaining light.
How is the xylem adapted for its function? (3)
- No end walls allows more water and minerals to flow. 2. Strong walls made from lignin. 3. Only moves upwards
What does the xylem carry?
Water and minerals
How is phloem adapted for its function?
- Small pores in the end walls to allow sap through. 2. Transports in both directions. (translocation)
What does phloem carry?
Food - mainly sugars.
What is transpiration?
The loss of water from a plant. It’s the movement out of the xylem.
What is translocation?
The movement of sugars through a plant in phloem both ways.
What is the process of transpiration?
Water evaporates and diffuses from the plant’s surface. More water is drawn up from the rest of the plant through xylem vessels to replace it. More water is drawn up from the roots and there’s a constant transpiration stream of water.
What affects transpiration? (4)
- Light intensity - brighter is more transpiration. 2. Temperature - hotter is more transpiration. 3. Air flow - stronger wind is more transpiration. 4. Humidity - the drier the air means more transpiration.
Who controls the stomata?
Guard cells
When is the stomata shut? (2)
- Lack of water. 2. Dark
When is the stomata open? (2)
- Lots of water. 2. Light
