YR10 core questions-cells Flashcards
What are villi?
Finger-like projections in the small intestine
What is the digestive system?
Organ system where food is broken down
What does the digestive system do?
Breaks down and absorbs food
Name eight organs of the digestive system
Mouth, salivary glands, oesophagus (gullet), stomach, intestines, liver, gallbladder, pancreas
What does bile do?
Neutralises stomach acid and emulsifies fats
What do glands in the digestive system do?
Release enzymes
Where are food molecules absorbed?
Small intestine
What is a nutrient?
A substance needed for growth, repair and metabolism
What is metabolism?
The sum of all the metabolic reactions in the body.
What are the seven nutrients of a balanced diet?
Carbohydrate, fat, protein, vitamins, minerals, fibre and water
What is a balanced diet?
A diet with a balanced proportion of nutrients
What is a simple sugar?
A carbohydrate consisting of either one or two sugar units e.g. glucose and sucrose
What is a carbohydrate?
Molecule made up of units of sugars containing carbon, hydrogen and oxygen
What is a complex carbohydrate?
Long chain of simple sugars bonded together
Give three examples of complex carbohydrates.
Starch, glycogen, cellulose
What chemical is used to test for carbohydrates?
Benedict’s solution
What is the colour change of Benedict’s solution when a sugar is present?
Blue to red
What chemical is used to test for starch?
Iodine solution
What is the colour iodine turns if starch is present?
Blue-black
What are the roles of proteins in living things?
Enzymes and building blocks of the body
Name 4 functions of proteins?
Muscle structure, hormones, antibodies, enzymes
What are amino acids?
The building blocks of proteins
What are the four main elements that proteins are made of?
Carbon, hydrogen, oxygen and nitrogen
What is the structure of proteins?
Chains of amino acids
What happens if a protein gets too hot?
It is denatured
What chemical is used to test for proteins?
Biuret reagent
What is the colour change of Biuret solution when a protein is present?
Blue to purple
What are lipids?
fats and oils
What are lipids made of?
1 molecule of glycerol bonded to 3 molecules of fatty acids
How do you test for lipids?
Ethanol test
What is an enzyme?
Biological catalyst
What is a catalyst?
Catalysts increase the rate of chemical reactions.
What is a substrate?
Substance that is changed by an enzyme
What is meant by ‘optimum conditions’?
the best conditions
What factors affect the action of an enzyme?
Temperature & pH
What is the optimum temperature for human enzymes?
37°C
How does high temperature inactivate enzymes?
It denatures protein which changes their shape
How does pH affect enzymes?
pH can affect the shape of the enzyme’s active site
What is a carbohydrase?
An enzyme that breaks down carbohydrates
What is amylase?
An enzyme that breaks down starch into simple sugars
Where is amylase made?
Salivary glands and the pancreas
What is a protease?
An enzyme that breaks down proteins
Where are proteases made?
The stomach (pepsin), pancreas and small intestine
Why do proteases work best in the stomach?
It is very acidic
What is a lipase
An enzyme that breaks down lipids
Where is lipase made?
Pancreas and small intestine.
Why do lipases and enzymes of the pancreas work best in the small intestine?
It is alkaline
How many chambers are there in the heart?
4
What are the chambers of the heart?
Right atrium, right ventricle, left atrium, left ventricle,
What structures in the heart prevent blood from flowing backwards?
Heart valves
How is heart rate controlled by the body?
A group of cells that act as a pacemaker.
Why is the human circulatory system called a double circulatory system?
Blood passes through the heart twice for every circuit around the body
What is oxygenated blood?
Blood containing a high level of oxygen
What is deoxygenated blood?
Blood containing a low level of oxygen
Which side of the heart pumps deoxygenated blood to the lungs?
Right side
Which side of the heart pumps oxygenated blood to the body?
left side
Which veins return deoxygenated blood to the heart?
Vena cava
Which artery takes deoxygenated blood the lungs?
Pulmonary artery
Which veins return oxygenated blood from the lungs to the heart?
Pulmonary veins
Which artery takes blood from the heart to the rest of the body?
Aorta
Which arteries supply oxygenated blood to the heart muscle?
Coronary arteries
Name the four main components of blood?
Red blood cells, white blood cells, platelets and plasma
What is haemoglobin?
Molecule that carries oxygen
Give three ways white blood cells protect the body?
Engulf pathogens, produce antibodies and produce antitoxins
What is the function of blood plasma?
Transports blood cells, platelets and dissolved substances around the body
Name seven dissolved substances that are transported in blood plasma?
Hormones, proteins, lipids, glucose, carbon dioxide, urea, lactic acid
What is urea?
Waste product
What is the function of platelets?
Forms blood clots which prevents blood leaving the body
What is an exothermic reaction?
A reaction that transfers thermal energy to the environment
Give an example of an exothermic reaction
Respiration
Give five ways cells use energy
Building up molecules and breaking down molecules, transferring heat, active transport, making muscles contract
What is glycogen?
stored glucose
Where is glycogen stored?
muscles and liver
What happens to your heart and breathing rate when you exercise?
increase
What happens to glycogen when you exercise?
Converted to glucose
What is an endothermic reaction?
A reaction that transfers thermal energy from the environment
Give an example of an endothermic reaction
Photosynthesis
What four factors can limit photosynthesis?
Light, temperature, carbon dioxide concentration, amount of chlorophyll in the leaf
How do plants use glucose?
For respiration and for making other molecules
What other molecules do plants use glucose to make
Carbohydrates like cellulose and starch, lipids, proteins
What is cellulose?
Complex sugar that strengthens plant cell walls
What is starch?
Stored glucose
