Science - Life Processes Flashcards
Write the word equation for aerobic respiration
glucose + oxygen -> carbon dioxide + water + (energy)
From which system does the body obtain glucose for respiration?
The digestive system
In which part of our cells does respiration mainly occur?
In the mitochondria
What are the products of respiration?
Carbon dioxide, water
How do we test for carbon dioxide?
Bubble through limewater; the limewater turns cloudy.
The word “aerobic” indicates the presence of which gas?
Oxygen
Which unit is energy usually measured in?
joules, J
How many joules are there in 1 kilojoule?
1000J
What is the symbol for kilojoule?
kJ (lower case k, capital J)
If a food is high in energy, which nutrient/s is it likely to contain?
Lipids/fats, carbohydrates
List the 7 nutrients needed by the human body
carbohydrates, proteins, lipids, vitamins, minerals, water, fibre
Foods high in which group help repair muscles?
Protein
Give 2 sources of vitamin C
Fruit and vegetables
Why is fibre needed in our diet?
Add bulk to food to help it pass through the digestive system; prevents constipation
Scurvy can occur when we don’t get enough of which vitamin?
C
Rice, potato and bread are good sources of
Carbohydrates
Sugar and starch are both types of
Carbohydrate
Meat, fish and nuts are good sources of
Protein
Which test do we use to detect for the presence of starch?
Iodine
When testing for starch what colour change indicates a positive result?
Brown to black
Which test do we use to detect for the presence of sugar?
Benedicts
When testing for sugar what colour change indicates a positive result?
Blue to red
Which test do we use to detect for the presence of protein?
Biuret
When testing for protein what colour change indicates a positive result?
Blue to purple
Which test do we use to detect for the presence of fats?
Ethanol
When testing for fats what change indicates a positive result?
Cloudy emulsion formed
Where does mechanical digestion mainly occur?
In the mouth
What is digestion?
The process of breaking down food into substances our body can absorb and use
List the organs the food will travel through on its way through the digestive system
Mouth, oesophogus, stomach, small intestine, large intestine, rectum, anus
Which nutrient starts to be chemically digested in the mouth?
Carbohydrate
Where does digestion of lipids take place?
Small intestine
Where does digestion of protein take place?
Stomach, small intestine
Which organ produces carbohydrase, protease and lipase?
Pancreas
What is the purpose of hydrochloric acid in the stomach?
Provides the right pH for the protease enzymes; kills bacteria
What is the purpose of bile in the digestive system?
Neutralise the acid which was added to food in the stomach to give the best pH for enzymes to work. Break down (emulsify) fat
Where is bile produced?
Liver
Where is bile stored?
Gall bladder
The site of maximum absorption in the digestive system is…
The small intestine
During digestion, carbohydrate is broken down into
Glucose
During digestion, protein is broken down into
Amino acid
Which enzyme digest protein?
Protease
During digestion, lipids are broken down into
Fatty acid and glycerol
Which enzyme digests carbohydrates?
Carbohydrase
Why is fibre not digested in the body?
Our bodies do not have enzymes that can digest fibre
Which enzyme digests fats?
Lipase
Why are vitamins and minerals not digested in the body?
They are small enough to be absorbed without digestion
What is the purpose of bacteria in our gut?
Digest food we cannot (e.g. cellulose) to give us essential nutrients (e.g. vitamin K)
How is the small intestine adapted to increase the rate of absorption?
Villi and microvilli to increase surface area; a good blood supply to transport nutrients; mucus for lubrication; glucose moves from a high concentration in the intestine to a lower concentration in the blood.
In which part of the digestive system does water and mineral absorption take place
The large intestine
What are the optimum conditions for amylase?
Neutral pH, 37 degreesC
What happens to an enzyme if it is boiled or exposed to a strong acid?
It is denatured
What is the scientific name for the windpipe?
Trachea
The trachea divides into two ________. These then divide into __________
Bronchi. Bronchioles
What are the air sacs at the end of each bronchiole called?
Alveoli
When we inhale, the volume inside the thorax ____________ so the pressure inside the thorax _____________
Increases. Decreases.
Breathing in and out is also known as…
ventilation
When we exhale, the diaphragm relaxes and moves upward/downward?
upward
Write the word equation for anaerobic respiration in cells
glucose -> lactic acid
What features do alveoli have to maximise gas exchange?
Large surface area; concentration gradient (oxygen and carbon dioxide can diffuse); good blood supply; capillary wall only 1 cell thick
Which releases more energy - aerobic or anaerobic respiration?
aerobic
What is anaerobic respiration in yeast cells known as?
Fermentation
Give an example of where fermentation is used
Brewing or baking
What are the products of the fermentation reaction?
Ethanol, carbon dioxide
