P1-Topic 2- Organisation Flashcards
What is the main function of the digestive system?
To digest food and absorb the nutrients
obtained from digestion.
What is the role of the pancreas and the salivary
gland in the digestive system?
2
The pancreas and the salivary gland are glands
which produce digestive juices containing
enzymes
What is the role of the stomach in the digestive system?2
Produces hydrochloric acid - which kills any bacteria present and provides the optimum acidic pH for the protease enzyme to function
What is the role of the small intestine in the
digestive system?
where soluble food molecules are absorbed into the bloodstream.
What is the role of the liver in the digestive system?3
Produces bile (stored in the gallbladder)
which emulsifies lipids
allows the lipase enzyme to work more efficiently
What is the role of the large intestine in the digestive system?
Absorbs water from undigested food,
producing faeces
What is the role of enzymes in the digestive system?2
act as biological catalysts which speed up the rate of biological reactions (the
breakdown of food) without being used up.
How does the shape of an enzyme affect its function?
Enzymes have a specific active site which is
complementary to their substrate.
What is metabolism?
The sum of all the reactions in a cell or an organism.
What types of metabolic reactions do enzymes
catalyse?3
● Building larger molecules from smaller molecules eg.
glucose to starch.
● Changing one molecule to another eg. glucose to
fructose.
● Breaking down larger molecules into smaller
molecules eg. carbohydrates to glucose.
What is the lock and key hypothesis of enzyme function?3
The shape of the enzyme active site and the
substrate are complementary, so can bind
together to form an enzyme-substrate complex.
How does temperature affect enzyme action?3
Up to a certain point, increasing temperature increases enzyme action,
as molecules have a higher kinetic energy.
Above a certain temperature, the shape of the active site is altered and the enzyme becomes
denatured,
so it can no longer catalyse the reaction. The
optimum temperature is around 37°
How does pH affect enzyme function?2
The optimum pH for most enzymes is 7 (apart
from proteases in the stomach).
If the pH is too extreme, the shape of the active site may be altered and the enzyme may no longer work.
Where are carbohydrases, proteases and lipases
produced in the body? 3
● Carbohydrases: amylase - salivary gland and pancreas; maltase - small intestine. ● Proteases: pepsin - stomach; others - pancreas and small intestine. ● Lipases: pancreas and small intestine
What is the role of carbohydrases in the digestive system?
2
break down carbohydrates into simple sugars
Amylase is a carbohydrase which breaks down starch.
Amylase breaks down starch into maltose, and maltase breaks down maltose into glucose
What is the role of proteases in the digestive system?
Proteases break down proteins into amino
acids.
What is the role of lipases in the digestive system?
Lipases break down lipids into fatty acids
and glycerol
How are the products of digestion used?2
The products of digestion are used to build new carbohydrates, lipids
and proteins.
Some glucose is used in respiration
Where is bile made and stored in the body?
Bile is made by the liver and stored in the
gallbladder
What is the role of bile in the digestive system?
● alkaline to neutralise hydrochloric acid from the stomach.
- Bile emulsifies lipids to form droplets - this
increases the surface area for the lipase enzyme to work on
equation for the rate of reaction
rate= change/time
What is the purpose of the circulatory system?
Carries oxygen and other useful
substances to bodily tissues, and
removes waste substances
How does the double circulatory system
work?2
-right ventricle pumps blood to the lungs where
gas exchange takes of of
oxygen and carbon dioxide takes place
-left ventricle pumps blood around the rest of the body.
Why is the double circulatory system important?2
It makes the circulatory system more efficient
- for example, oxygenated blood can be pumped around the body at a
higher pressure by the left ventricle.
What are the four main blood vessels associated with
the heart?4
● Aorta (left) - carries oxygenated blood from the heart to the body.
● Pulmonary vein (left) - carries oxygenated blood from the lungs to the heart.
● Vena cava (right) - carries deoxygenated blood from the body to the heart.
● Pulmonary artery (right) - carries deoxygenated blood from the heart to the lungs.
What is the purpose of valves in the heart?
Prevent the backflow of blood
What is the purpose of coronary arteries?
supply the heart muscle with oxygenated blood.
Describe the process of blood flow through the heart 3
● Blood enters the right atrium (vena cava) and the left atrium (pulmonary vein)
● The atria contract, forcing blood into the ventricles and
causing valves to shut
● After the ventricles contract, blood in the right ventricle enters the pulmonary artery (to the lungs) and blood in the left ventricle enters the aorta (to the body).
How is the heart rate controlled?2
Heart rate is controlled by a group of cells in the right atrium which act as a pacemaker.
They release waves of electrical activity
which cause the heart muscle to contract
How can an abnormal heart rhythm be treated?
Irregular heart rhythms can be treated using an artificial pacemaker,
sends out electrical signals to correct the heart’s rhythm.
How are arteries adapted for their function?3
● Function: carry blood away from the heart.
● Thick muscle layer - adds strength to resist high
pressure.
● Thick elastic layer - allows arteries to stretch
and recoil - in order to withstand high pressure.
How are veins adapted for their function?3
● Function: carry blood towards the heart
● Wide lumen - enables low pressure
● Valves - prevent backflow of blood
How are capillaries adapted for their function?3
● Function: enable transfer of substances between
the blood and tissues.
● Walls are one cell thick - short diffusion path.
● Permeable walls - substances can diffuse across.
● Narrow lumen - blood moves slowly - more time
for diffusion.
How would you calculate the rate of blood flow?
Volume of blood / number of minutes
Where are the lungs found in the body?2
located in the thorax (within the chest).
protected by the ribcage
separated from the rest of the abdomen by the diaphragm
What tissues make up the gas exchange system?
6
● Trachea ● Intercostal muscles ● Bronchi ● Bronchioles ● Alveoli ● Diaphragm
Explain how the lungs are ventilated by the action of intercostal muscles 5
● Intercostal muscles contract
● Ribcage moves upwards and outwards
● Diaphragm flattens and volume of the chest increases
● Increased volume results in decreased pressure
● Air is drawn into lungs down pressure gradient
The inverse occurs when air moves out of the lungs.
Describe how gas exchange occurs at the alveoli 2
● Oxygen diffuses from the alveoli into the capillary bloodstream down its concentration gradient.
● Carbon dioxide diffuses from the capillary into
the alveoli down its concentration gradient
Describe how alveoli are adapted for gas exchange
3
● Small and arranged in clusters - larger surface
area.
● Rich blood supply - maintains concentration
gradient.
● Thin alveolar wall - short diffusion pathway.
How would you calculate the breathing rate
Number of breaths / number of minutes
How can life situations affect health?2
life factors such as location, gender, financial status, ethnic group and
healthcare provision can impact a person’s
mental and physical health.
Give examples of how health problems can interact
4
● Infection with certain viruses can lead to cancer eg. hepatitis infections can lead to liver cancer.
● A compromised immune system (eg. due to cancer) can lead to a higher risk of infection with communicable diseases.
● Immune reactions caused by a pathogen can trigger allergic reactions (asthma,Skin rashes)
● Problems with physical health can lead to mental health issues.
What is a causal mechanism?
A mechanism which demonstrates how one
factor biologically influences another
How do diet, smoking and exercise affect the
development of cardiovascular disease?3
● Diet: high levels of LDL cholesterol causes arteries to become blocked, increasing blood pressure and the risk of
a heart attack.
● Smoking: nicotine increases heart rate; other chemicals damage the artery lining and increase blood pressure.
● Exercise: lowers blood pressure, reducing strain on the heart
How does obesity affect the development of type 2
diabetes?
● Obesity is strongly linked with type 2 diabetes - a disease in which the body
stops responding to insulin
How does alcohol affect liver and brain function?3
● Excessive long-term alcohol use may lead
to liver cirrhosis (scarring of the liver).
● Increases risk of liver cancer with fatty liver
● Damages brain tissue and nerve cells.
How does smoking affect the development of lung disease and lung cancer?2
● Tar in tobacco can damage the alveoli of the
lungs, leading to chronic obstructive pulmonary disease (COPD).
● Tar also damages the cells which line the
lungs, leading to lung cance
How do smoking and alcohol affect unborn
babies?2
● Carbon monoxide from tobacco smoke reduces the
amount of oxygen the foetus receives, which can lead
to premature birth or stillbirth.
● Alcohol passes across the placenta and damages the
developing foetus. Once born, the baby may have a
number of deformities and health problems as part of
foetal alcohol syndrome.
How is epidermal tissue adapted for its function?2
- covers the entire plant
- has a waxy cuticle which helps reduce water loss from the leaf surface. by evaporation
How is palisade mesophyll tissue
adapted for its function? 3
- found underneath the epidermal tissue
- contains lots of chloroplasts which allows photosynthesis to progress at a rapid rate.
- positioned at the top of the leaf so receive a lot of light
How is spongy mesophyll tissue adapted
for its function? 2
-found underneath the palisade mesophyll
-has lots of air spaces which allow gases (oxygen and carbon dioxide) to diffuse in
and out
How is the xylem adapted for its function?
- hollow tube - allows the movement of water and mineral ions from the roots to the leaves.
● Strengthened by lignin - makes the vessel strong and waterproof.
● Has bordered pits - allow minerals to be transported to specific places.
How is the phloem adapted for its function?3
● Made up of elongated living cells.
● Cells have sieve plates that connect them
together - cell sap can move through plates
into other cells.
● Sieve tube cells have few organelles to allow
the efficient transport of substances
How is meristem tissue adapted for its function? 2
-found at the tips of shoots and roots
-Made up of stem cells which can
differentiate into many different cell types,
allowing the plant to grow.
What tissues does the leaf organ contain?6
● Epidermis ● Palisade mesophyll ● Spongy mesophyll ● Xylem ● Phloem ● Guard cells
What is the function of guard cells?
Guard cells control the opening and closing
of the stomata, according to the water
content of the plant
How are stomata adapted for their function?3
Stomata allow the control of gaseous exchange and
water loss from the leaf.
● More stomata on the base of the leaf - minimises
water loss as this side is cooler and shaded.
● Have guard cells which control their opening and
closing.
How are root hair cells adapted for their function?3
Root hair cells allow the uptake of water and mineral ions from the soil.
● Large surface area - maximises rate of
absorption.
● Contain lots of mitochondria – release energy
for active transport of mineral ions
What is translocation?
Translocation is the movement of
dissolved sugars from the leaves to other
parts of the plant
What is transpiration?
Transpiration is the evaporation of water
vapour from the surface of a plant.
How does transpiration work?3
● Water evaporates from the leaf surface via the
stomata.
● Water molecules cohere together - more water is
pulled up the xylem in an unbroken column.
● More water is taken up from the soil - creating a
continuous transpiration stream
How does temperature affect the rate of
transpiration?2
Increasing the temperature increases the rate
of transpiration.
● Higher rate of evaporation and diffusion of
water - therefore rate of transpiration is
increased.
How does humidity affect the rate of transpiration?3
Increasing relative humidity decreases the rate of
transpiration.
● High relative humidity will reduce the water
vapour concentration gradient. The rate of
evaporation will decrease, and so will the rate of
transpiration.
How does wind speed affect the rate of
transpiration?
increasing wind speed/air movement increases the
rate of transpiration.
● Increased air movement lowers water vapour
concentration outside of the leaf. This increases the
water vapour concentration gradient, thereby
increasing the rate of evaporation and transpiration.
How does light intensity affect the rate of
transpiration?
3
Increasing the light intensity increases the rate of
transpiration.
● The rate of photosynthesis increases, so more
stomata open.
This allows the rate of evaporation
to increase, increasing the rate of transpiration
