organisation Flashcards
what is the other name for subcellular structures and what do they form
organelles that form cells
what is the job of epithelial tissue
covering the body surface like skin or small intestine
what is the job of muscle tissue
contract and relax to move parts of our body
what is the job of glandular tissue
making and secreting hormones or enzymes
what is an example of an organ and what does it do
stomach that breaks down proteins and kills microorganisms
what is the definition of an organ
a group of different tissues that work together to perform a common function
explain why the digestive system is considered an organ system
it consists of a group of organs
that work together to perform the common function of digesting and absorbing our food
eg:the pancreas releases digestive enzymes that help break down food molecules while the small intestine absorbs the nutrients
why are enzymes so important for us
chemical reactions we need for life are very slow and increasing temp will speed up non useful reactions and use alot of energy
what are enzymes made of
large proteins of amino acids
what is a catalyst
substance that increases speed of a reaction without being used up
what makes enzymes specific about the reaction they speed up
their active site has a complementary shape to the substrate of the reaction
what is the lock and key model
substrate must fit perfectly into active site like lock perfectly fits into a lock
what is the induced fit model
the enzyme slightly changes shape as it binds to the substrate-complementary
how does temp affect rate of enzyme reaction
rate of reaction increases at 1st part of curve as all particles have more kinetic energy and sucessful collision number is increased and particles react with enough energy to react.After 37 degrees the rate drops as high temp breaks bonds holding enzymes together so active site also changes shape.if it changes shape enough it becomes denatured (permanent and isnt able to bind to the substrate)
affect on ph on enzyme rate of reaction
at too high and too low ph rate of reaction is lowered as active site begins to change shape slowing down reactions as substrate can still fit but not as well .
what are carbs used for/where do we find them
energy we need to move around and carry out chemical reactions
we find them in starchy food/bread pasta potatoes or fruits
what do fats do and where are they found
in oily fish nuts, seeds, avocados
they insulate us /protect our organs and provide energy
what are proteins used for/found
growth and repair
used for energy in emergency
found in nuts and seeds/meat and fish and legumes
minerals vs vitamins
vitamins are organic -produced by living organisms
minerals- simpler inorganic molecules
what is the role of bile
neutralising acid and emulsifiying fats into fat droplets
what does amylase break down and to what
it breaks down starch into smaller simpler sugars like maltose
where is amylase found
in the small intestine
pancreas
salivary glands
what does protease break down and into what
proteins(like nuts) into amino acids
what does lipase break down and into what
fats into fatty acids and glycerol
where are lipids produced
pancreas and small intestine
How does bile help with the digestion of lipids?
it emulsifies lipids which increase the surface area for lipase enzymes to break them down
list the journey of food in digestion
mouth-oesophagus-stomach-small intestine-large intestine-rectum-anus
how does the mouth help digest food
chewing breaksdown food physically and salivary glands secrete amylase which breaks down carbs
what is the role of the stomach
-churns and contracts muscular walls t push and mix food around
-produces pepsin which breaks down proteins
-produces hcl which kill bacteria and provide suitable ph for pepsin to work
what is the role of the small intestine
absorbs digested food into bloodstream
what does the pancreas do
secretes/makes most enzymes into small intestine as pancreatic juices
what is the role of the gall bladder
secretes bile into small intestine
this bile neutralises acid in the stomach as it is alkali making ph ideal for digestive enzymes to function
it emulsifies fats as well
where is bile made/ stored and released into
made in the liver
stored into gall bladder
released into small intestine
what is the function of the small intestine after food is digested into many small pieces
absorbs food across intestine lining(exchange surface) straight into bloodstream
what are the adaptations of villi
-finger like projections that massively increase small intestine surface area-allows digested food to be absorbed into the bloodstream much quicker
-single layer of surface cells thick so nutrients only need to diffuse short distances
-good blood supply-maintains conc gradient
what does the large intestine do
absorbs excess water from the watery remains of undigestable remnants in the small intestine leaving behind faeces which is stored in the rectum before being removed
what are the 2 main roles of the digestive system
Digestion-process of breaking down large food molecules into smaller molecules
Absorption - process of absorbing these small food molecules into the body
how does chewing help in digestion
it makes food easier to swallow
it increases sa for enzymes to act on
what are some ways villi are adapted to absorb nutrients into the body
There are many villi, which gives them a large total surface area over which to absorb nutrients
They have a single layer of cells on their surface, which means nutrients only have to diffuse a short distance.
They have a good blood supply which maintains a strong concentration gradient between the lumen and the blood
The cells lining the villi have microvilli on their surface, which further increases the surface area
how do we prepare our sample for food tests
get food and use mortar and pestle and put crushed food into a beaker with distilled water and stir it with a glass rod until some dissolves. Filter out solution using funnel lined with filter paper to get rid of the solid bits of food.we now have our sample
bendedicks test
prepare 5cm3 of sample and 75 degrees water bath
add 10 drops of benedicks solution into test tube and place it in a water bath for 5 mins-use test tube rack to place it in water bath
what colour will benedick solution turn to if sugar is present
normal-stays blue
if sugars are present-brick red
how to prepare carb/starch test
get 5cm3 of sample
add few drops of iodine soution and shake
what is the colour change for carb test if starch is present
normal-browny orange
if starch is present-blue-black
prepare the test for proteins
add 2 cm3 of sample to test tube
add 2cm3 of biuret solution turning it blue shaking gently
what is the colour change if protein is present in the biuret test
blue-pink/purple
what is the role of the lungs
to get the oxygen we need from the air around us into our bloodstream where it can be transported to the rest of the body
describe the journey of air throughout our body
air passes through mouth or nose
then down our trachea
then divides between our 2 bronchi
further dividing between our bronchioles
it then reaches the site of gas exchange which is our alveoli
what are the adaptations of the alveoli
-they are 1 cell thick-reduced diffusion distance-so oxygen and c02 diffuse across at a faster rate
-they have a large sa-there are so many
-have moist walls allowing gases to dissolve-increasing rate of diffusion
-have a steep concentration gradient
How are alveoli adapted for efficient gas exchange?
Their walls are only one cell thick…
…which provides a short distance for diffusion
There are many of them giving a large total surface area
They are moist, which allows the gases to dissolve, and therefore diffuse more easily
Which substance inside red blood cells does oxygen bind to?
haemoglobin
how is c02 transported around the blood
dissolved in blood plasma
what is the role of the circulatory system and what does it rely on
to transport oxygen and nutrients to body tissues
it relies on blood(carries o2 and nutrients) / blood vessels(hold blood)/ heart(keeps blood moving through vessels)
why is the circulatory system called the double circulatory system
2 loops
-one carries deoxygenated blood from heart to the lungs-gains oxygen and flows back to heart
-the other carries the oxygenated blood to the tissues where it gives up the oxygen becoming deoxygenated and flows back to heart
what is the heart made of
chambers called atrium(at the top) and ventricles(at the bottom)
what are the role of valves
between chambers and vessels we find valves preventing backflow of blood
describe the journey of blood through the heart
right side-deoxygenated
vena cava (from loop around body)
right atrium
right ventricle
pulmonary artery(lungs)
left side-oxygenated
pulmonary vein(from lungs)
left atrium
left ventricle aorta(to body)
what cells act as pacemaker/ and what happens in certain peoples
cells in the right atrium which produce small electrical impulses in the walls of the heart causing them to contract-keeping beat steady
some peoples dont work so artificial pacemakers can be placed under skin just above the heart- they have wires that carries current down to heart telling it to contract regularly
what is the difference between an artery and a vein
vein carries blood to the heart
artery carries blood away from the heart
where does heart get its own oxyenated blood supply from
coronary arteries that branch off the aorta circing the heart ensuring the muscle tissue has all the nutrients/oxygen it needs
which ventricle has thicker walls and why
the left because it has to pump blood at high pressure all around the body
The journey of blood around the body
Body tissues ➔ vena cava ➔ right atrium ➔ right ventricle ➔ pulmonary artery ➔ lungs ➔ pulmonary vein ➔ left atrium ➔ left ventricle ➔ aorta ➔ body tissues
what are the 3 blood vessels
what do the 3 blood vessels do
-arteries-carry blood away from the heart
-capillaries-exchange nutrients +oxygen with tissues
-veins- carry blood back to the heart
how are artery adapted to their function
blood is at high pressures
they have thick layer of muscle tissue to keep them strong/direct blood flow
they have thick layer of elastic tissue to be able to stretch and recoil
walls are quite thick vs its lumen
what is the size of capillaries and what do they do
-small
-exchange substances with our cells
-take away Co2 and give nutrients and oxygen
how are capillaries adapted and how does this adaptation help
1)walls are single cell thick
2)permeable-so substances can easily diffuse through them
3)lumen are tiny but are so many the total cross sectional area is huge(much higher than the arteries)-so blood is at lower pressure and slower giving it time to exchange substances
how does the size of veins/lumen compare with other blood vessels
large
have biggest lumens
what are the adaptations of veins for their function
thin walls-small layers of elastic fibres and smooth muscle
the blood they carry is at low pressure so the walls don’t need to be strong
-have valves
what are nutrients that are exchanged between the blood in the capillaries and the body tissues?
amino acids and glucose
what are waste products that are exchanged between the blood in the capillaries, and the body tissues?
Carbon dioxide
Urea
In which order does blood flow through the three types of blood vessels?
Heart ➔ artery ➔ capillary ➔ veins ➔ heart
what are the 4 things that make up our blood
white blood cells
red blood cells
platelets
plasma
how much volume do red blood cells take up of our blood
50%
what is the role of red blood cells and what is it used for
carry oxygen from lungs to body tissues to be used for cellular respiration
how does rbc carry oxygen from lungs to body tissues
red pigment haemoglobin binds to oxygen (oxyhaemoglobin)and splits back into oxygen and haemoglobin when travelling bodies tissues so oxygen can freely diffuse into our tissues
what are the 2 adaptations of red blood cells
1)no nucleus creating more space for haemoglobin and oxygen
2)shaped as a biconcave disk to give them large sa to absorb oxygen
what are 3 ways white blood cells defend us against infection
phagocytosis-engulf pathogens
producing antibodies-bind and help destroy them
producing antitoxins-neutralise toxins
how much of our blood do white blood cells make up
<1% of our blood
what do white blood cells do
defend us against infection
what are platelets and what do they do
they are small fragment of cells that float around in our blood waiting till we get a cut where they act like glue patching it up]
blood clotting(stops microorganisms getting in/blood pouring out )
what volume of blood does plasma take up
just over 50%
what is plasma and what does plasma do to the blood
-the pale straw coloured liquid makes blood watery so it can flow
-it carries all the components of blood(rbc /wbc/platelets)
-carries nutrients(glucose and amino acids)
-carries waste products(co2 and urea)
/hormones/proteins and antibodies and antitoxins produced by wbc
how much blood does an adult have flowing through their circulatory system at 1 given time
5l
why is getting stabbed a problem
may not be blood left over to deliver adequate oxygen to the tissues
what are the 2 types of blood a stab survivor can be given+pros and cons
-artificial blood-blood substitute with salt water and adds volume to our circulatory system but can only replace 1/3 of our blood as there are no red blood cells
-blood transfusion-real blood donated
what blood components have nucleus vs which dont
do
white blood cells
dont
rbc
platelets
what are some nutrients that would be found in plasma
glucose, amino acids, fatty acids, and glycerol
what are examples of cardiovascular diseases and what are they
coronary heart disease
faulty valves
heart attacks
heart failure
they are diseases related with the heart and the blood vessels
what are treatments for cardiovascular diseases
stents
statins
replacement valves
replacement hearts
what is coronary heart disease and what is used to treat it
coronary arteries get blocked by build up of cholesterol so lumen becomes narrower and less blood flows through and less oxygen reaches heart putting strain on heart increasing chance of heart attack
stents or statins
what is a stent and what are its pros and cons
an expandable tube that can be placed inside the arteries and hold them open to make the blood keep flowing
pros
-surgery is quick
-effective for a long time
-effective almost immediately
cons
-require surgery-could lead to heart attack or infection
-could develop blood clot near the stent
what is a statin
Pros and cons
a medication that alters balance of cholesterol in the bloodstream -decrease amount of bad cholesterol and increase amount of good cholesterol
pros-
lowers risk of chd , strokes abd heart attacks
cons-
must be taken regularly for years
-cause side effects(headaches or kidney failure)
-can take months to see positive effects
what are problems we can get with valves
-blood leaking back as it cant close properly
-not enough blood passing though
what are ways we can replace faulty valves
biological valves
mechanical(manmade) valves
both require surgery-risk of blood clot
what is heart failure
when heart cant pump blood around body properly
how can we replace faulty hearts
with a new heart which can either be
-artificial or
- biological
what are the pros and cons of heart replacements
-artificial are only temporary
-biological cant be pigs or cows so we need a donor-which may take ages
-heart must also be accepted by immune system/could potentially be rejected as it sees heart as foreign and tries to destroy it
-immune system wont try and destroy it as it is made of metal and plastic
What are factors that cause good health
Balanced diet
Sufficient exercise or sleep
Access to vaccine/medecine
What is disease
A condition that caused ill health which can be caused by eg
Bad diet-diabetes
Or unrelated to our lifestyle like chicken pox
What are the 2 types of diseases
Communicable and non communicable
What are communicable diseases and examples
Diseases that can spread from person to person causes by viruses ,bacteria ,parasites and fungi
Examples are common cold
Malaria
What are non communicable diseases and example
Diseases not spread between people
Eg asthma,chd cancer and diabetes
More commonly starting slowly and lasting long sometimes never going away
What are non communicable diseases and example
Diseases not spread between people
Eg asthma,chd cancer and diabetes
More commonly starting slowly and lasting long sometimes never going away
What are ways that non communicable and communicable diseases can combine
Immune system weakened making people catch communicable diseases more often than those without
What is a risk factor
Something that increase chance someone will develop a certain disease
What is obesity a risk factor for
Heart attacks
Diabetes
What are tumours
Abnormal mass of cells from uncontrolled cell division and growth
What is a benign tumour vs malignant
Benign don’t spread or invade tissues
Malignant invade tissues
Malignant spread
Malignant cause secondary tumours
What are 4 risk factors for cancer
Smoking
Obesity
Uv light exposure
Drinking alcohol
What is the structure of a leaf and function
Leaves are the site of photosynthesis
They need lots of co2 and water
-co2 diffuses into leaf through stomata at the bottom of the leaf
-these stomata are scattered by the lower epidermis which is a layer of epidermal tissue
-co2 enters spongy mesophyll tissue in the middle with lots of air gaps for gas to diffuse easily to the next layer
-palisade mesophyll layer packed with chloroplasts as this is where most photosynthesis happens
-above this there is the upper epidermis which are transparent to let sunlight through to chloroplasts
What happens when sugar molecules are produce by photosynthesis
Phloem carries them to the rest of the plant
What causes water loss Et the bottom of the leaves and what do they do to counter this
Stomata-keep them open for as short as possible
Why do leaves need stomata open
To absorb as much co2 as they need
What happens when guard cells are hydrated/unhydrated
-They are turgid so the gap between them increases allowing more co2 to go through
-guard cells lose water making them flaccid causing them to close conserving water vapour
Why do guard cells close at night
As they are light sensitive and at night there is no light so photosynthesis is not taking place so co2 is not needed
Why are stomata on the underside of the leaf
It is more shaded and therefore cooler so less likely chance that water will evaporate
What are meristem tissues where are they found and what do they help the plant do
They are a plants stem cells which are found on the growing tips of the roots and shoots of the plants and differentiate into cells so plant can grow
What is the movement of cell sap called
Translocation
What do plant cells have in their end walls to allow cell sap to pass cell sap into phloem
Pores
What does xylem transport in a plant
Water and dissolved mineral ions
How do root hair cells absorb mineral ions from the soil?
Active transport
How do root hair cells absorb mineral ions from the soil?
Active transport
Which substance are xylem cells reinforced with to make them stronger?
Lignin
What is transpiration?
The evaporation of water from the leaves
What is translocation
Transportation of sugars around plants by phloem
What are sugars used for when they reach the cells
Energy
Or
Stored for energy later
What differentiates phloem from xylem
Xylem have no cell ends with pores and are dead cells
They are also strengthened by lignin
What is the role of xylem
They transport water and dissolved mineral ions from roots to stem to leaves where it is used in photosynthesis
What is the evaporation of water from leaves
Transpiration
what factors increase and decrease rate of transpiration
increase
temperature
light intensity
air flow
humidity
how does air flow affect rate of transpiration
if it is windy the water that evaporates will be blown away quickly keeping conc gradient high increasing rate of transpiration
what is humidity and how does humidity affect rate of transpiration
it is the measure of water vapour in the air
the concentration gradient is less steep so decreases meaning less water diffuses out so less rate of transpiration
how does light intensity affect rate of transpiration
brighter it is more photosynthesis takes place so more stomata open to let in co2 needed for it.More water can evaporate as stomata are open
