Organisation Flashcards
Paper 1 - B2
What is the role of the small intestine in the digestive system?
To digest food using enzymes and for small food molecules to be absorbed into the blood
What is the main nutrient group digested in the stomach?
Proteins
What is the purpose of hydrochloric acid in the stomach?
To create acidic conditions for protease enzymes to work
What is the role of the pancreas in digestion?
To produce enzymes
What are enzymes?
Protein molecules that act as biological catalysts/speed up reactions
Name the theory for how enzymes work
‘lock and key’ theory
Name two places in the body where the amylase enzyme is produced
salivary glands and pancreas
Where in the body is the protease enzyme
produced?
In the stomach
Where in the body is the lipase enzyme produced?
Small intestine
Which molecule is broken down by amylase? What are the products?
Starch into simple sugars
Which molecule is broken down by lipase? What are the products?
Lipids (fats) into glycerol and fatty acids
Which molecule is broken down by protease? What are the products?
Proteins into amino acids
What are the products of digestion used for?
Making new molecules (and glucose for respiration)
Which organ produces bile and which organ stores it?
Produced in the liver, stored in the gall bladder
What effect does bile have on stomach acid?
It neutralises it because it is alkaline
What is the role of bile in fat digestion?
It emulsifies fat to form small droplets which increase the surface area so the lipase enzyme can work at a faster rate
Name the test for sugars in food and state the colour change for a positive test
Benedict’s solution; blue to brick-red
Name the test for starch in food and state the colour change for a positive test
Iodine solution; brown to blue-black
Name the test for protein in food and state the colour change for a positive test
Biuret solution; pale blue to lilac
What chemical can be used to test for fats in food? What will happen in the test if fats are present?
Ethanol; solution turns cloudy
Name the part of an enzyme which is affected by high temperatures and extremes of pH
Active site
What are enzymes made of?
Protein molecule/chain of amino acids
Name two factors that affect the rate of an enzyme reaction
Temperature and pH
What happens to enzymes at very high temperatures and how does this affect how they work?
They denature, meaning that the shape of the active site changes and the reacting molecule no longer fits
What is meant by a double circulatory system?
The left side of the heart pumps blood around the body and the right side pumps blood to the lungs (so blood goes through heart twice for each complete circulation)
Where does the right ventricle of the heart pump blood to?
The lungs
Where does the left ventricle pump blood to?
Around the body
Why is the wall of the left ventricle thicker than the wall of the right ventricle?
The left ventricle pumps blood all around the body, so the muscle is larger
Name the blood vessel that carries blood from the heart to the rest of the body
Aorta
Name the blood vessel that carries blood from the heart to the lungs
pulmonary artery
Name the blood vessel that carries blood from the lungs to the heart
pulmonary vein
Name the blood vessel that carries blood back to the heart from the body
Vena cava
Name the tube that carries oxygen from the nose to the lungs, sometimes called the windpipe.
Trachea
Name the tubes that connect the trachea to the alveoli in the lungs
Bronchi
What is the name of the tiny air sacs in the lungs?
Alveoli
What is the name of the group of cells in the heart that controls the natural resting heart rate?
Pacemaker
Where in the heart is the natural pacemaker located?
In the right atrium
What is the name of the bottom two chambers of the heart and what is their function?
Ventricles; to pump blood
What is the name of the top two chambers of the heart and what is their function?
Atriums; to receive blood
Which of the three types of blood vessels carry blood away from the heart?
Arteries
Which of the three types of blood vessels carry blood towards the heart?
Veins
Which of the three types of blood vessels is where substances are exchanged between blood and tissues?
Capillaries
Give two differences between arteries and veins.
Arteries have a smaller lumen (hole) and a thicker layer of muscle/elastic tissue in the wall than veins
What are the 4 components of blood?
Red blood cells, white blood cells, plasma, platelets
What are the substances carried in the plasma of the blood?
Carbon dioxide (not oxygen); vitamins; minerals; amino acids; proteins; antibodies; hormones; water etc.
What is the function of red blood cells?
To transport oxygen around the body
What is the function of white blood cells?
To defend the body against pathogens (produce antibodies, antitoxins and carry out phagocytosis)
What is the function of platelets?
Blood clotting
How are red blood cells adapted to perform their function?
Contain haemoglobin; no nucleus; biconcave disc shape; small & can change shape
How does coronary heart disease start in the body?
Layers of fatty material build up in the coronary arteries
Name the arteries that become blocked in heart disease
Coronary arteries
Name the mechanical device that can be used to keep the coronary arteries open to treat heart disease.
A stent
How can a blocked coronary artery lead to heart disease?
The heart muscle is starved of oxygen and can no longer respire
Name the drugs used to reduce blood cholesterol and slow down the rate that fatty material is deposited in the arteries
Statins
What problems might be caused by a leaky heart valve?
Blood flow/heart pumping may be inefficient; backflow of blood through the heart
When might patients need an artificial heart?
When they have heart failure and are waiting for a donor organ
Give one advantage and one disadvantage of a heart transplant
Advantages: Long-term fix for heart disease - improves
quality of life/prevents death;
Disadvantages: Body may reject the organ; risks of surgery
What is health?
The state of physical and mental well-being
What is a non-communicable disease?
A disease that cannot be spread and is not caused by a pathogen
List 3 factors that can lead to ill health
Poor diet; stress; disease
What problem would be seen in a person with a weak immune system?
They would be more likely to suffer from infectious diseases
What type of pathogen can be the trigger for certain cancers?
Viruses
What two types of allergies can be triggered by immune reactions initially caused by a pathogen?
Skin rashes and asthma
What is meant by a ‘risk factor’ for a disease?
Something that increases the chance of developing a disease e.g. smoking, obesity, excessive alcohol, carcinogens
Which two organs can be affected by excessive alcohol consumption?
Liver and brain
Which organ is most severely effected by smoking, and what disease can develop here?
Lungs - lung disease and cancer
What type of disease is caused by chemicals called carcinogens?
Cancer
What is cancer?
Changes in cells (mutations in DNA) leading to uncontrolled growth and cell division
What is a benign tumour?
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?
Cancerous growths that invade neighbouring tissues and spread to other parts of the body in the blood forming secondary tumours.
Other than lifestyle factors, what else can affect the risk of developing certain cancers?
Genetic factors
What is the function of the epidermal layer in the leaf of a plant?
Transparent layer allowing sunlight through to the palisade cells. Protection and produces the waxy cuticle.
What is the function of the palisade mesophyll layer in the leaf of a plant?
Main photosynthesising layer. Packed with chloroplasts to absorb sunlight. Near surface of leaf
What is the function of the spongy mesophyll layer in the leaf of a plant?
Contains air spaces for diffusion of gases into and out of cells of the leaf
What is the function of the xylem in plants?
To transport water from the roots to the leaves
What is the function of the phloem in plants?
To transport sugars/products of photosynthesis from the leaves around the plant
What is the function of guard cells in the leaf of plants?
To control the opening and closing of the stomata to let gases in/out of the leaf
Name the process by which water is transported from the roots to the leaves in a plant
Transpiration
Name the process by which sugars are transported from the leaves around a plant
Translocation
Name 4 factors that increase the rate of transpiration in plants
Low humidity; higher temperatures; increased air movement; higher light intensity
Describe the structure of xylem vessels
Hollow tubes made from dead cells and strengthened by lignin
Describe the structure of phloem tissue
Tubes of elongated cells with pores in the end walls so that cell sap can travel between the cells
