B2 - Cell Organisation Flashcards
A group of cells is called what?
Tissue
A group of tissue is called what?
An organ
A group of organs is called what?
Organ system
A group of organ systems is called what?
Organism
What does muscular tissue do?
Contract to move whatever it’s attached to
What does glandular tissue do?
Makes and secretes hormones and enzymes
What does epithelial tissue do?
Cover organs and parts of the body
What are enzymes?
Catalysts
What are catalysts?
Substances which increase the speed of a reaction without being changed by the reaction
What are enzymes made of?
Large proteins
What are proteins made of?
Chains of amino acids
What do enzymes have that vary between different types and dictate which type of reactions the catalyse?
Active sites which are a specific shape for a specific substrate
What is the ‘lock and key’ model of enzyme reactions?
When you draw the enzyme and substrate so they fit perfectly together like puzzle pieces
Why is the ‘lock and key’ model slightly inaccurate?
Enzymes will change their shape slightly when they bind to the substrate for a tighter fit
What two factors can heavily affect enzymes’ reactivity?
pH and temperature
What happens when the enzyme exceeds the optimum temperature or pH?
It can become denatured
What happens to make an enzyme denatured?
The active site changes
Why do digestive enzymes break down starch, proteins and fat?
Because the molecules are too big to pass through the digestive system walls
What is starch?
Carbohydrate
What are lipids?
Fats and oils
What is the name of the enzyme that converts carbohydrates?
Carbohydrase
What do carbohydrates get broken down into?
Sugars like maltose and dextrins
Where is amylase made? (3)
Salivary glands, pancreas, small intestine
What is the name of the enzyme that converts proteins?
Protease
What are proteins broken down into?
Amino acids
Where is protease made? (3)
Stomach, pancreas, small intestine
What is the name of the enzyme that converts lipids?
Lipase
What are lipids converted into?
Glycerol and fatty acids
Where is lipase made? (2)
Pancreas, small intestine
What does bile do?
Neutralises acids and emulsifies fats
Where is bile made?
Liver
Where is bile stored?
Gall bladder
What does the bile neutralise and where?
Hydrochloric acid in the stomach
What does ‘emulsified fats’ mean?
Breaks fats down into tiny droplets
Why does the bike emulsify fats?
The fats have a larger surface area for lipase to work on and digestion becomes faster
What enzyme do the salivary glands produce?
Amylase
What enzyme does the stomach produce?
Protease
What does the liver produce that affects digestion?
Bile
What enzymes does the pancreas produce?
Protease, amylase and lipase
What enzymes does the small intestine produce?
Protease, amylase and lipase
What does the stomach do other than produce protease?
Pummels food with muscular walls and produces hydrochloric acid
Why does the stomach produce hydrochloric acid?
To kill bacteria and give the right pH for protease
What does the gall bladder do?
Store bile then release it into the small intestine
What does the large intestine do?
Absorb excess water from the food
What does the small intestine do other than producing enzymes?
Complete digestion with the enzymes, it is where digested food is absorbed into the blood
Where are the lungs?
The thorax, the top part of your body
What separates the upper and lower parts of you body?
The diaphragm
What protects the lungs?
The ribcage
Where does inhaled air go first?
The trachea
Where does air go after the trachea?
The bronchi: The trachea splits into two bronchi, one for each lung
Where does inhaled air go after the bronchi?
The bronchioles: the bronchi split into even smaller tubes
Where does inhaled air go after the bronchioles?
The alveoli: small air sacs at the end of the bronchioles
Where does inhaled air go after the alveoli?
The bloodstream
How does air get from the alveoli to the blood stream?
Diffusion
What is in the blood that arrives at the alveoli?
Carbon dioxide
What is in the blood that leaves the alveoli?
Oxygen
What is in the blood that arrives at the body cells?
Oxygen
What is in the blood that leaves the body cells?
Carbon dioxide
Breaths per minute =
Number of breaths/number of minutes
What type of blood flows through the right side of the heart?
Deoxygenated
What type of blood flows through the left side of the heart?
Oxygenated
Where does the blood go that leave the right side of the heart?
The lungs
Where does the blood go that leaves the left side of the heart?
The rest of the body
What does the heart do to pump blood?
Contract
What are the walls of the heart mostly made of?
Muscle tissue
What does the heart contain to keep blood flowing in the right direction?
Valves
How many chambers are in the heart?
Four
What are the upper chambers called?
The atria (singular: atrium)
What are the lower chambers of the heart called?
Ventricles
Through which vein does blood enter the right atrium?
Vena cava
Through what artery does blood leave the right ventricle?
Pulmonary artery
Through what vein does blood enter the left atrium?
Pulmonary vein
Through what artery does blood leave the left ventricle?
Aorta
What is a pacemaker?
Something that controls our resting heart rate
Where are our natural pacemakers?
In the right atrium wall
How do our natural pacemakers control our heart rate?
By sending an electrical impulse telling the heart’s muscle cells when to contract
What happens if our natural pacemakers fail?
We can be fitted with an artificial pacemaker
What are three types of blood vessels?
Arteries, veins and capillaries
What do arteries do?
Carry blood away from the heart
What do veins do?
Carry blood to the heart
What do capillaries do?
They are involved in transferring things between blood and tissues
Which type of blood vessel carries blood at a high pressure?
Arteries
Why do arteries have a high pressure?
The walls are strong and elastic and there isn’t much space inside the artery
What is a lumen?
The space inside of the blood vessel that blood flows through
What are the walls of arteries like?
Thick layers of muscle and electric fibres that allow them to stretch
Do arteries or veins have larger lumen?
Veins
What are vein walls like?
Thinner than artery walls
Does blood flow through veins at a low or a high pressure?
Low
What do veins contain to prevent back flow?
Valves
What two properties do capillaries have to make diffusion easier?
Permeable walls, walls are only one cell thick
What are the four key components of blood?
Red blood cells, white blood cells, platelets and plasma
What is the function of the red blood cells?
To carry oxygen around the body
What is the shape of red blood cells?
Biconcave disc
What common sub-cellular structure do red blood cells not have and why?
Nucleus, to allow for more room for the oxygen
What five red blood cells their red colour?
Haemoglobin
What happens when oxygen from the lungs enters the red blood cell?
It bonds with the haemoglobin to form oxyhaemoglobin
What happens when oxygen leaves the red blood cells to go to the bodily cells?
The oxyhaemoglobin splits up into oxygen and haemoglobin and the oxygen diffuses out
What is the function of the white blood cells?
To defend against infection
What are the three things a white blood cell might do to a pathogen?
Engulf it, produce antibodies, produce antitoxins
What do white blood cells have that red blood cells don’t?
Nucleus
What is the function of the platelets?
To clot a wound
What actually are platelets?
Small fragments of cells
What is the function of plasma in the blood?
It carries everything
What things are contained in the plasma? (10)
Red blood cells, white blood cells, platelets, nutrients, carbon dioxide, urea, hormones, proteins, antibodies, antitoxins
What cardiovascular disease do stents and statins treat?
Coronary heart disease
What is coronary heart disease?
When the coronary arteries that give the heart oxygen become blocked up by layers of fatty material
What is a result of coronary heart disease?
Lack of oxygen to heart which can lead to a heart attack
What does a stent do?
It pushes the fat against the artery wall and allows more room in the lumen for blood to flow through
What are the advantages of stents?
Long lasting, short recovery time after surgery
What are disadvantages and risks of stents?
Operational complications, infection after surgery, blood clot near stent
What are statins?
Drugs that can reduce the amount of bad cholesterol
What is the bad type of cholesterol called?
LDL cholesterol
What are the advantages of statins?
Reduce risk of strokes, coronary heart disease and heart attacks; help produce more of the good types of cholesterol
What are the disadvantages of statins?
Long term drug makes forgetting to take them a possibility; can cause side effects like headaches, memory loss, liver damage, kidney failure; effect isn’t instant
What can heart failure be treat with?
Artificial hearts
What are artificial hearts normally replaced by?
Donor hearts
What are the advantages of an artificial heart?
Don’t rely on a matching person’s death; less likely to be rejected
What are the disadvantages of an artificial heart?
Surgery can lead to bleeding or infection; aren’t as realisable as natural hearts; can result in blood clots so patient has to take blood thinning drugs; blood thinning drugs can lead to serious blood loss in accidents
What can damage heart valves?
Heart attacks, infection, old age
What are the effects of valve damage?
Too stiff to let blood through at all, or too leaky to prevent back flow
How do you solve the problem of a fault heart valve?
Replacing the valve
Are replacement valves mechanical or biological?
Can be either
What is an advantage of replacing a heart valve?
Far less drastic than a heart transplant
What is a disadvantage of replacing a heart valve?
Still a major surgery with issues like blood clotting
What is artificial blood?
A substitute for blood such as saline
When is artificial blood used?
When a person suffers serious blood loss
How does artificial blood help when blood has been lost?
It maintains the volume of blood until the body produces more blood cells
What might a patient still need after receiving artificial blood?
A blood transfusion of real blood
What would artificial blood ideally do that scientists are still working on?
Replace the function of the lost blood cells
What is the definition of health?
The state of physical and mental wellbeing
What is a pathogen?
A microorganism that causes disease
What are communicable diseases?
Diseases that can spread from person to person, and also animals
What are non-communicable diseases?
Diseases that cannot be spread between people
What is a person with problems in their immune system more vulnerable to and why?
Communicable diseases because their body isn’t capable of fighting off the pathogens
What are some factors that can affect your health other than disease?
Diet, exercise, stress, access to medical treatment and access to disease preventative measures
What are risk factors?
Things that increase your chance of getting a disease
Are risk factors a greater contributor to communicable or non-communicable diseases?
Non-communicable
What are some risk factors that are known to not just increase the risk but directly cause diseases?
Smoking - cardiovascular disease, lung disease, lung cancer
Obesity - Type 2 Diabetes
Excessive drinking - Liver disease, damage brain nerve cells
Carcinogens - Things like radiation that can cause cancer
What is cancer?
When a cancerous tumour grows
What is a tumour?
Uncontrolled cell growth and division
What are the two types of rumours?
Benign and malignant
Which type of tumour is cancerous?
Malignant
How benign tumours behave?
They stay in a single place, growing until they run out of room, and are the less dangerous type
How do malignant tumours behave?
It grows and spread to healthy tissues, the cells will travel elsewhere via the bloodstream, they are dangerous and cancerous and can be fatal
List four lifestyle based risk factor for cancer.
Smoking, obesity, UV exposure, certain viral infections
What is a non-lifestyle risk factor that is beyond our control?
Genetics
What are the three main organs of a plant?
Stem, roots, leaves and flowers
What is the epidermal tissue?
It covers the whole plant
What is the palisade mesophyll tissue?
The part of the leaf where photosynthesis takes place
What is the spongy mesophyll tissue?
Part of the leaf containing large air spaces for gases to diffuse in and out
What are the xylem and phloem?
Tubes in the plant that transport things like water, minerals and food
What is the meristem tissue?
Found at the growing tips of shoots and roots and has unspecialised cells
What does the leaf’s waxy cuticle do?
Cover the epidermal tissue to reduce water loss by evaporation
What is different about the upper epidermal layer of the leaf?
It is transparent, to allow light through the palisade layer for photosynthesis
What does the palisade layer have lots of?
Chloroplasts
What additional structures are on the lower epidermal layer?
Stomata and guard cells
What do the stomata on the bottom of the leaf do?
Let carbon dioxide diffuse into the leaf
What do the guard cells on the bottom of the leaf do?
Control the opening and closing of the stomata depending on environmental conditions
What do the phloem tubes transport?
Food
What is the process of transporting food within the phloem called?
Translocation
Which directions does translocation go in?
Either
What do xylem tubes transport?
Water
What is the process of water being transported through the xylem called?
Transpiration stream
Which directions does the transpiration stream go in?
Up only
What is transpiration?
The loss of water from a plant
What is transpiration caused by?
Evaporation and diffusion
Where does most transpiration take place?
The leaves
How does water escape from the plant?
The evaporated water goes out through the stomata in the leaves, because there is less water vapour outside the leaves so it diffuses
What are the four main things that can affect transpiration?
Light intensity, temperature, air flow and humidity
Describe the relationship between light intensity and transpiration rate.
The brighter the light, the faster the transpiration rate
How does light affect transpiration?
Stomata exist to let carbon dioxide in for photosynthesis. Photosynthesis can not occur when it is dark, so the stomata close and as a result a lot less water can escape
Describe the relationship between temperature and transpiration rate.
The warmer it is, the faster the rate of transpiration is.
How does temperature affect transpiration?
The warmer the water particles are the more energy they have to move, so they can move quicker out of the plant.
Describe the relationship between air flow and the rate of transpiration.
The stronger the wind around a plant, the greater the rate of transpiration
How does air flow affect transpiration?
If there’s a good air flow then the previously diffuses water vapour outside of a leaf will be swept away. This means there will be a consistently small amount of water vapour outside of the leaf, maintains a large concentration gradient and faster diffusion
Describe the relationship between humidity and transpiration rate.
The drier the air around a leaf, the faster the rate of transpiration
How does humidity affect transpiration?
Humid air already contains lots of water vapour, creating a smaller concentration gradient and a slower rate of diffusion
What is the rate of transpiration typically directly proportional to and can therefore be measured using it?
Uptake of water by the roots
What is the shape of a guard cell?
Like a kidney
What happens when the plant has lots of water?
The guard cells go plump and turgid to let out water vapour
What happens when the plant is short of water?
The guard cells become flaccid and close to hold in the water vapour
