Animal Tissues, Organs and Organ Systems - AQA Biology GCSE

The main function of the digestive system is __________.

to digest food and absorb the nutrients obtained from digestion.

The role of the pancreas and the salivary gland in the digestive system is __________.

to produce digestive juices containing enzymes.

The role of the stomach in the digestive system is __________.

to produce hydrochloric acid which kills bacteria and provides the optimal pH for protease to function.

The role of the small intestine in the digestive system is __________.

the site where soluble food molecules are absorbed into the bloodstream.

The role of the liver in the digestive system is __________.

to produce bile which emulsifies lipids and allows the lipase enzyme to work more efficiently.

The role of the large intestine in the digestive system is __________.

to absorb water from undigested food, producing faeces.

The role of enzymes in the digestive system is __________.

to act as biological catalysts which speed up the rate of breakdown of food without being used up.

The shape of an enzyme affects its function by __________.

having a specific active site which is complementary to its substrate.

Metabolism is __________.

the sum of all the reactions in a cell or an organism.

Enzymes catalyse metabolic reactions which include __________.

building larger molecules from smaller molecules, changing one molecule into another, and breaking down larger molecules into smaller ones.

The lock and key hypothesis of enzyme function states that __________.

the shape of the enzyme active site and the substrate are complementary, allowing them to form an enzyme-substrate complex.

Temperature affects enzyme action by __________.

increasing enzyme action up to a certain point, after which the active site is altered and the enzyme becomes denatured.

The optimum temperature for enzyme action is __________.

around 37°.

The optimum pH for most enzymes is __________.

7, except for proteases in the stomach.

Where are carbohydrases, proteases and lipases produced in the body? __________.

Carbohydrases: amylase in salivary gland and pancreas, maltase in small intestine; Proteases: pepsin in stomach, others in pancreas and small intestine; Lipases: pancreas and small intestine.

The role of carbohydrases in the digestive system is __________.

to break down carbohydrates into monosaccharides and disaccharides.

The role of proteases in the digestive system is __________.

to break down proteins into amino acids.

The role of lipases in the digestive system is __________.

to break down lipids into fatty acids and glycerol.

The products of digestion are used to __________.

build bigger molecules such as carbohydrates and proteins.

Bile is made by the __________ and stored in the ______________.

liver; gallbladder.

The role of bile in the digestive system is __________.

to neutralise hydrochloric acid and emulsify lipids.

The heart is __________.

an organ that pumps blood around the body.

The purpose of the circulatory system is __________.

to carry oxygen and useful substances to bodily tissues and remove waste substances.

The double circulatory system works by __________.

having one pathway for blood to the lungs and another for blood to the tissues.

Blood pumped by the right ventricle goes to __________.

the lungs.

Blood pumped by the left ventricle goes to __________.

the body tissues.

The double circulatory system is important because __________.

it makes the circulatory system more efficient by allowing higher pressure for oxygenated blood.

The heart has __________ chambers called __________.

4; right atrium, right ventricle, left atrium, left ventricle.

The wall of the left ventricle is thicker because __________.

it pumps blood at a higher pressure around the whole body.

The four main blood vessels associated with the heart are __________.

Aorta, pulmonary vein, vena cava, pulmonary artery.

The purpose of valves in the heart is __________.

to prevent the backflow of blood.

Coronary arteries supply __________.

the heart muscle with oxygenated blood.

Blood flow through the heart starts in __________ via __________, and ends in __________ via __________.

the right atrium; vena cava; the left ventricle; aorta.

The natural resting heart rate is approximately __________.

70 beats per minute.

The heart rate is controlled by __________.

a group of cells in the right atrium that act as a pacemaker.

An abnormal heart rhythm can be treated with __________.

an artificial pacemaker.

The three types of blood vessel in the body are __________.

arteries, veins, capillaries.

Arteries are adapted for their function by having __________.

a thick muscle and elastic layer to withstand high pressure.

Veins are adapted for their function by having __________.

a wide lumen and valves to prevent backflow.

Capillaries are adapted for their function by having __________.

walls that are one cell thick for short diffusion paths.

The rate of blood flow can be calculated by __________.

volume of blood divided by number of minutes.

The lungs are found in __________.

the thorax (within the chest).

The gas exchange system consists of tissues such as __________.

trachea, intercostal muscles, bronchi, bronchioles, alveoli, diaphragm.

The lungs are ventilated by intercostal muscles contracting, which causes __________.

the ribcage to move upwards, increasing chest volume and decreasing pressure.

Gas exchange occurs at the alveoli when __________.

oxygen diffuses into the capillary bloodstream and carbon dioxide diffuses into the alveoli.

Alveoli are adapted for gas exchange by being __________.

small, arranged in clusters for a larger surface area.

The breathing rate can be calculated by __________.

Number of breaths divided by number of minutes.

Plasma is __________.

a yellow liquid within blood that transports substances around the body.

Substances transported by plasma include __________.

red blood cells, white blood cells, platelets, carbon dioxide, urea, products of digestion.

The purpose of red blood cells in blood is __________.

the transport of oxygen around the body.

Red blood cells are adapted for their function by having __________.

a biconcave shape and no nucleus.

The purpose of white blood cells in blood is __________.

to protect the body from invading pathogens.

White blood cells are adapted for their function by __________.

having a nucleus and can produce antibodies.

The purpose of platelets in blood is __________.

to aid the clotting of blood at the site of a wound.

The function of platelets is important because __________.

they prevent excessive bleeding and protect against infection.

Coronary heart disease occurs when __________.

the coronary arteries become blocked with fatty material.

A stent is __________.

a metal mesh tube inserted into a blocked artery to keep it open.

Advantages of stents include __________.

quick recovery and lower heart attack risk.

Statins are __________.

drugs that reduce the level of LDL cholesterol.

The purpose of heart bypass surgery is __________.

to replace blocked coronary arteries with veins.

Leaky heart valves cause __________.

blood to flow in the wrong direction, reducing the heart's efficiency.

Mechanical valves can be described as __________.

made of metal or polymers.

Biological valves are __________.

taken from animals or other humans.

Artificial hearts are designed to __________.

support a patient’s heart while waiting for a donor heart.

Health is defined as __________.

the state of physical and mental wellbeing.

A communicable disease is __________.

a disease caused by a pathogen that can be transmitted from one person to another.

A non-communicable disease is __________.

a disease that cannot be transmitted from person to person.

Diet can affect health by __________.

leading to deficiencies or obesity.

Stress affects health by __________.

being linked to heart diseases and mental health issues.

Life situations that affect health include __________.

location, gender, financial status, and healthcare provision.

Risk factors are __________.

aspects that increase the risk of a disease.

A causal mechanism demonstrates __________.

how one factor biologically influences another.

Obesity is linked to __________.

the onset of type 2 diabetes.

Alcohol can affect liver function by __________.

leading to liver cirrhosis and increasing cancer risk.

Smoking can affect the lungs by __________.

damaging alveoli and leading to chronic obstructive pulmonary disease (COPD).