Revision cards Flashcards
What are cells?
Cells are the fundamental units (building blocks) of all living organisms
What are tissues?
Tissues are groups of similar cells that act harmoniously to perform a similar function
What are organs?
Organs are groups of distinct tissues that work together to perform a specific function
What are organ systems?
Organ systems are groups of organs that work together to perform a particular role
What are organisms?
Organisms are the highest level of organisation in a multicellular organism consisting of several organ systems
Which tissue covers the inside and the outside of an organ?
Epithelial tissue
Which tissue churns food and digestive juices of the stomach together?
Muscular tissue
Which tissue can contract to bring about force and motion?
Muscular tissue
Which tissue produces the digestive juices that break down food?
Glandular tissue
Which tissue is capable of photosynthesis?
Mesophyll tissue
Which tissue includes skin in humans and the waxy covering of some plants?
Epidermal tissue
What is the role of the stomach?
To digest food
What is the role of the small intestine?
To digest food and absorb nutrients
What is the role of the large intestine?
To absorb water molecule and produce faeces
What is the role of glands in digestion?
To produce digestive enzymes
What is the role of the liver?
To produce bile
Name 3 of the tissues in the stomach
Muscular - contracts to move stomach contents around for digestion
Glandular - produces digestive juices that break down stomach contents
Epithelial - lines stomach to protect it from harsh environment
To catalyse (speed up) a reaction, what must bind to what?
The reacting chemical (substrate) must bind to the enzyme’s active site.
What is the equation for the rate of reaction?
Rate of reaction = change in mass/ change in time
Increasing the ___________ of a working enzyme initially increases the ________.
Enzymes have an _______ temperature and, once this is reached, the activity _________.
Then, last a certain ___________, the ______ ____ changes shape, and the enzyme is _________.
Temperature
Activity
Optimum
Decreases
Temperature
Active site
Denatured
What do digestive enzymes do?
Digestive enzymes catalyse the breakdown of large, insoluble food molecules into smaller, soluble (can be dissolved) molecules that are then small enough to be absorbed into the bloodstream.
What are the three main digestive enzymes?
Amylase
Protease
Lipase
The main type of carbohydrate is starch.
What is starch broken down by?
Amylase
What is starch broken down into?
Maltose (and other sugars)
Where is amylase made?
Small intestine
Pancreas
Salivary glands
_____________ break carbohydrates down into sugars.
Amylase is a type of ____________ that breaks down starch in our bodies.
Carbohydrases
Carbohydrase
What are proteins broken down by?
Proteases (digestive enzymes)
What are proteins broken down into?
Amino acids
Where are proteases made?
Small intestine
Pancreas
Stomach (pepsin)
Where is pepsin?
What does it do?
Pepsin is a stomach enzyme that helps to break down / digest proteins
What are lipids broken down by?
Lipases
What are lipids broken down into?
Glycerol
Fatty acids
Where is lipase produced?
Small intestine
Pancreas
Describe how bile emulsifies fats
Bike breaks up fats (like oil) into tiny droplets, through a process called emulsification.
The tiny droplets have a higher surface area than the original fat drop, which increases the rate of the reactions (catalysed by lipase) that break fats down.
Describe how bile neutralises acid
Bike neutralises acid from the stomach to stop enzymes denaturing (losing activity).
What is bile?
An alkaline substance stored in the gallbladder after being made in the liver. Enzymes in the small intestine operate best in alkaline conditions, so bile helps to do this
What reagent is used to test for Starch?
Iodine
What reagent is used to test for Lipids?
Sudan III
What reagent is used to test for Proteins?
Biuret
What reagent is used to test for Sugars?
Benedict’s
What colour will the iodine solution turn if starch is present?
Blue-black
What colour will the Benedict’s solution turn if sugar is present?
Small amount present = green
More sugar present = yellow
A lot of sugar present = brick red
What colour will a biuret solution turn if proteins are present?
Purple
What colour will Sudan III solution turn if lipids are present?
red-stained oil layer will float on the water surface
If ethanol = white colours emulsion
Arteries do what?
Transport blood away from the heart
Veins do what?
Carry blood towards/ into your heart
Capillaries do what?
Connect arteries and veins and form a network allowing the exchange of oxygen, nutrients, and waste products between the blood and body cells
Describe an artery
Thick walls
Small lumen
Thicker layer of muscle and elastic fibres
Describe a vein
Relatively thin walls
Large lumen
Often have valves
Describe a capillary
Walls a single cell thick
Tiny vessel with narrow lumen
Why is it called the double circulatory system?
Blood passes through the heart twice per circuit
Define alveoli
Tiny air sacs in your lungs that exchange gases
Give two ways alveoli are adapted for efficient gaseous exchange:
1) Surrounded by a network of capillaries.
- maintains steepest concentration gradient in both directions, making gas exchange more rapid and effective.
2) Layer of cells between air in lungs and and blood in capillaries is also very thin (only one cell wide), allowing diffusion to take place over the shortest distance possible.
What is the order for lungs?
Trachea -> bronchi -> bronchioles -> alveoli
Air breathed in through trachea (windpipe). Trachea divides into 2 tubes called bronchi. Bronchi divide to form bronchioles. These divide until they end up in tiny air sacs called alveoli.
Blood is a tissue made up of a fluid called plasma, which has 3 parts to it/ suspended in it. It also carries many dissolved substances around your body. Name the three parts:
Red blood cells
White blood cells
Platelets
How are red blood cells adapted? Give 3
1) Biconcave shape - increased surface area to volume ratio for diffusion.
2) Haemoglobin - red pigment that binds to oxygen
3) No nucleus - more space for haemoglobin
Define white blood cells
Blood cells involved in the immune system of your body. They engulf pathogens and make antibodies and antitoxins.
What do platelets do?
Fragments of cells in the blood that trigger wound blood clotting
What is a communicable disease?
Can be spread from one person to another
What is a non-communicable disease?
Can’t be spread from one person to another
Name 4 pathogens
Virus
Fungi
Protist
Bacteria
Which type of pathogen causes Malaria?
Protists
Which type of pathogen causes Salmonella?
Bacteria
Which type of pathogen causes Rose Black Spot?
Fungi
Which type of pathogen causes flu?
Virus
Name a disease transported by water:
Cholera
How does coronary heart disease happen?
The coronary arteries narrow due to a build-up of fatty deposits. This reduces blood flow and leads to a lack of oxygen to the heart.
How is CHD (Coronary Heart Disease treated? Give 2 ways
Stents
Statins
Why are stents inserted?
To keep coronary arteries open
Why are statins taken?
Decrease cholesterol levels in the blood.
What can coronary heart disease lead to?
A heart attack
Give 2 advantages of using stents:
lower risk of heart attack
Effective for a long time
Surgery recovery time is relatively quick
Give 2 disadvantages of using stents:
Risk of complications during the operation (eg. heart attack)
Risk of infection
Risk of developing a blood clot
Need replacing
What is LDL and HDL cholesterol?
Cholesterol is an essential type of lipid that your body produces and needs to function properly. however, too much of a ceratin type (LDL) can cause health problems. It can cause fatty deposits to form inside arteries -> CHD.
HDL cholesterol is good for you as it helps to remove LDL cholesterol from the blood
How do statins work?
Reduce amount of ‘bad’ cholesterol present in the bloodstream. This slows down the rate of fatty deposits forming.
Give 2 advantages of statins:
Reduced risk of strokes, coronary heart disease, and heart attacks.
Increase amount of HDL cholestrol or ‘good’ cholesterol in your bloodstream.
Some studies suggest that statins may also help prevent some other diseases.
Relatively cheap
Give 2 disadvantages of statins:
Must be taken regularly
Can cause negative side effects, eg. headaches, kidney failure, liver damage, memory loss
The effect of statins isn’t instant, as it takes time.
What happens to heart valves in heart valve disease?
Become faulty, either by leaking or unable to fully open.
What is cancer?
A group of diseases, where changes in cells lead to uncontrolled growth and cell division.
What are the two types of tumour? Describe.
Malignant - spreads throughout the body in the blood
Benign - stays in a specific part of the body
Describe the spongy mesophyll
Many air spaces, which help with gas exchange throughout the leaf.
Describe the stomata
Found in the lower epidermis. Specialised guard cells can close them (eg. hot weather to reduce water loss)
Guard cells turgid = stomata open
Guard cells flaccid = stomata close
What covers the outer surface of leaves (as well as the rest of the plant)?
Epidermal tissue
Row of cells in the upper epidermis. They’re exposed to a lot of sunlight. Has many chloroplasts to maximise energy created by photosynthesis.
Palisade mesophyll
What is a haploid nucleus?
Contains 23 chromosomes
What is a Diploid nucleus?
Contains 46 chromosomes
What is transpiration?
Water loss through plant leaves
What is translocation?
The transport of food substances made in the leaves to the rest of the plant for a) intermediate use or b) storage
What factors affect the rate of transpiration? Give 3
Temperature - carries water away from plant leaves
Light intensity - makes water evaporate quicker
Humidity - more water in air so harder for water to evaporate
Air flow - Carrie’s water away from plant leaves
What apparatus is used to calculate transportation rate?
Potometer
Translocation happens through…
phloem tubes
Give two facts about phloem tubes
Made up of columns of elongated cells with holes in end walls, allowing cell sap (containing sugars, salts, and amino acids) to pass between the cells.
Bidirectional (up and down the plant)
Give two ways xylem tubes are adapted to their function
No end walls / long tube for ease of transport
Lignin / in the cell walls. Strengthens and waterproofs the elongated cells.
Dead - the tubes are hollow and, therefore, their resistance to water flow is low.
How are root hair cells adapted? Give 2
Long projections / increase surface area.
Mitochondria - ensures enough energy for active transport of minerals up the stem.
Give 4 ways the body prevents pathogens:
Skin
Mucus
Stomach acid
Tears
What happens in phagocytosis?
White blood cell finds pathogen + engulfs it by changing shape.
White blood cell ingests (absorbs) the pathogen, destroying it.
What happens with antitoxins?
Some bacteria produce toxins that damage cells and tissues. Immune system responds by producing antitoxins, which neutralises the toxins released by the bacteria and prevents them from causing harm.
What happens with antibodies?
White blood cells recognise foreign antigens (proteins) on the surface of pathogens and produces protein molecules called antibodies.
Antibodies are specific to particular pathogens.
Antibodies have a ..
Complementary shape to the antigen and lock onto the pathogen, effectively ‘tagging’ them. This causes the microorganisms to cluster, allowing other white blood cells to cure and injest (eat) them.
Give three ways photosynthesis is affected:
Temperature
Light intesity
Chlorophyll concentration
CO2 concentration
Name two limiting factors in photosynthesis
Winter - temp
Warm and bright - more co2 concentration taken up
Mineral/deficient soil / lack of minerals to produce lots of chlorophyll - chlorophyll concentration
Night - light intensity
Glucose produced by photosynthesis is mainly used by respiration in plants. However, it can be converted into: Give 2
Proteins (growth and repair)
Starch (insoluble and stored in stems and leaves and roots)
Fats and oils (stored in structures such as seeds)
Cellulose (strengthens cell walls)
Light intensity equation?
LI = 1/ distance squared
Give two reasons why organisms might need energy:
Contraction
Homeostasis
Construction
In plant and yeast cells, glucose is converted into ethanol and carbon dioxide. In yeast cells, this is called fermentation. What is the equation?
Glucose -> ethanol and CO2
Anaerobic respiration equation and explanation?
Happens when insufficient oxygen reaches muscles during periods of intense activity
Glucose -> lactic acid
What do cells do of water leaves to balance concentrations?
Shrinks
What is metabolism?
Combination of all chemical processes in an organism
What is homeostasis?
Regulation of internal conditions to maintain optimal conditions for enzyme action and cell function.
What happens to your respiration during exercise? Give 3
Blood vessels dilate to allow more blood to reach muscles.
Breath volume increases to increase gas exchange.
Increased breathing rate / delivers more blood containing glucose and oxygen to the muscles.
Increase in breath rate to increase gas exchange in lungs, more oxygen taken in and CO2 released.
What are antigens
Proteins found on surfaces of cells. White blood cells recognise foreign pathogens and produce protein molecules called antibodies.
What is the difference of concentrations of water in osmosis potato practical?
10cm cubed of a 0.5 molar sugar solution
10 cm cubes of a 0.25 molar sugar solution
Distilled water
Distilled Water potato gains mass
Concentrated potato loses
Equal potato stays same
What does bile do
Emulsify fat droplets to increase surface area so lipase can digest fat more easily and neutralises acid
Difference between gamete and zygote?
Gamete unfertilised reproductive cells
Zygote fertilised egg
Starch is broken down by what into what?
Broken down by amylase into maltose
Proteins are broken down by what into what?
Protease into amino acids
Lipids are broken down by what into what?
Lipase into glycerol and fatty acids
