Structure and Functions in Living Organisms Flashcards
Level of organisation
Cells, Tissues, Organs, Organ System
- A cell is a group of organelles working together to perform the same function
- A tissue is a group of cells working together to perform the same function
- An organ is a group of tissues working together to perform the same function
- An organ system is a group of organs working together to perform the same function
What elements are found in carbohydrates (glucose)+ how to test for it
- Carbon, Hydrogen and Oxygen
- Heat solution in water and add Benedict’s solution, turns from blue to:
- green or yellow in low concentration
- brick red in high concentration
What elements are found in protein + how to test for it
- Carbon, Hydrogen, Oxygen and Nitrogen
- Add biuret solution, turns from blue to purple
What elements are found in lipids + how to test for it
- Carbon, Hydrogen and Oxygen
- Add ethanol + water to the solution and shake, if positive test a milky white emulsion forms
What is starch made up of and how to test for it
- Made up of simple sugars (glucose) joint together
- Add iodine solution, if positive test the sample should turn blue-black
What are enzymes
- Biological catalysts
- Which speed up the rate of reaction without being used up
What is metabolism
It’s the rate at which chemical reactions take place in the body
What’s an active site
An area of an enzyme where substrate attaches
What is diffusion
- net movement of particles
- from area of high concentration to an area of low concentration
The effect of too high temperature on enzyme activity + the effects of too high or too low pH on enzyme activity
- Decreases activity
- Enzyme denatures and substrate can no longer fit the active site
What are the factors affecting diffusion
- Temperature
- Concentration gradient
- Surface area to volume ratio
- Distance
What is osmosis
- net movement of water molecules
- across a partially permeable membrane
- from area of high water conc. to area of lower water conc.
What is active transport
- net movement of particles
- from area of low concentration to an area of high concentration
- requiring energy
What’s a limiting factor
- Factor in a reaction which is in the shortest supply
- Lack of this factor is the reason why the rate of reaction no longer increases
What is the process of photosynthesis
- Photosynthesis is the process where plants make their own ‘food’ (the food it produces is glucose)
- Chloroplast contains chlorophyll which absorbs sunlight and uses the energy to convert CO2 and H2O into glucose and water
Why is rate of photosynthesis low in the morning
- Carbon dioxide levels are high
- Temperature is a limiting factor
- Low temperature inhibits enzyme activity
Why is rate of photosynthesis high at midday
- High temp maximises enzyme activity
- Carbon dioxide is a limiting factor as it is in the shortest supply
Whats magnesium needed for in plants
- Needed to produce chlorophyll in plants
- Not enough leads to leaves yellowing
Whats nitrogen needed for in plants
- Nitrates = source of nitrogen which is needed to make amino acids for protein
- Not enough causes stunted growth and yellowing of leaves
What’s contained in the top half of a leaf + their functions
- Waxy Cuticle: Prevent evapouration of water
- Upper epidermis: Transparent to allow light to enter leaf
- Palisade Mesophyll: Contains lots of chloroplast for photosynthesis
What’s contained in the bottom half of a leaf + their functions
- Spongy mesophyll air spaces: Allows gases to diffuse
- Xylem: Allows entry of water into leaf by tranpiration stream
- Phloem: Takes away glucose produced from photosynthesis
- Guard cells: Controls opening and closing of stomata
- Stomata: Allows CO2 to enter the leaf
How is a leafs structure better adapted for photosynthesis
- Thin; so gases don’t have to diffuse far
- Large surface area; so it can absorb more light
Carbohydrates
source + function
- Pasta, rice
- Provides energy
Proteins
source + function
- Meat
- Important for growth and repair of muscles
Lipids / Fats
source + function
- Butter
- Provides energy + provides insulation
Vitamins A, C and D
source + function
A:
* Liver
* Helps improve vision
C:
* Oranges
* Helps to prevent scurvy
D:
* Eggs
* Needed for strong bones
LOE
Mineral Ions
Calcium + Iron
source + function
Calcium:
* Milk
* Needed to make strong teeth + bones
Iron:
* Red meats
* Needed to make haemoglobin for healthy blood
Fibre
source + function
- Fruits + Vegetables
- Aids movement of food through gut
Water
function
- Constant supply to replaces water loss from sweating, urinating, breathing
Bile function
- PRODUCED in liver, STORED in gall bladder and RELEASED into the small intestine
- Bile is alkali, it NEUTRALISES the hydrochloric acid from the stomach
- BIle EMULSIFIES fat - it breaks down large lipid molecules into smaller ones to increase surface area
What is peristalsis
- Muscular contractions that squeeze boluses of food through your gut
The Alimentary Canal
What happens in the mouth?
- Teeth break down food into smaller parts
- Enzyme amylase in the saliva start to break down starch
The Alimentary Canal
What happens in the stomach?
- Stomach contracts to break down food into smaller pieces
- Proteases start to break down proteins in the stomach
- Produces hydrochloric acid to kill bacteria
The Alimentary Canal
What happens in the pancreas?
- Pancreas secretes digestive enzymes into small intestine;
- Proteases (protein), Amylase (carbs) and Lipase (lipids)
The Alimentary Canal
What happens in the small intestine?
- Absorbs nutrients into the body
- First part is the deodenum and last part is called the ileum
- The walls of the SI are covered in villi which have a large surface area for more absorption
The Alimentary Canal
What happens in the large intestine?
- This is where excess water is absorbed
- After water’s absorbed, the undigested food leaves the body as faeces
How is the structure of villi important
- Villi is covered in microvilli which** increases the SA for absorption** even more
- Each villus contains capillaries to maintain quick absorption of nutrients
- In the middle of the villus is a lacteal which is responsible for absorbing fat
What is respiration?
- It’s the process of transferring energy from glucose
- This transferred energy is made into ATP which provides energy to cells
Aerobic respiration word + chemical equation
Oxygen+Glucose->Carbon Dioxide+Water+ATP
6O2 + C6H12O6 —> 6CO2 + 6H20 + ATP
Anaerobic respiration word equation in humans + plants
Glucose —–> Lactic acid + energy
Glucose —–> Ethanol + Carbon Dioxide + energy
What do the goblet cells and cilia do?
- Goblet cells secrete mucus which traps bacteris
- Cilia, located in the trachea and lungs, have hair like projections that waft the mucus up to your mouth
What happens when you breathe in?
- Intercostal muscles + diaphragm contract/flattens out
- Thorax increases in volume + ribs move up and out
- This decreases the pressure drawing air in
What happens when you breathe out?
- Intercostal muscles + diaphragm relax
- Thorax decreases in volume + ribs move down and in
- This increases the pressure, forcing air out
How are alveoli adapted for gas exchange?
- They have large surface area
- Thin walls to short diffusion pathway
- Moist to dissolve gases
- Great blood supply
How does smoking effect the body?
- Contains carcinogens leads to lung cancer
- Smoking damages the walls of alveoli —> decreasing surface area for gas exchange —> disease called emphysema
- Tar causes cilia to paralyse —> build up of mucus and pathogens —> bronchitis and smokers cough
- Carbon monoxide binds irreversably to haemoglobin —> reducing amount of oxygen —> heart rate increases to make up, high blood pressure —> increased risk of coronary heart disease and heart attacks
Components of blood
- Red blood cells
- White blood cells
- Plasma
- Platelets
What do platelets do + how do they do it?
- Clot the blood at the site of a wound
- In a clot, platelets are held together by a mesh of protein called fibrin
What substances are transported in plasma?
- (soluble products) Glucose, Amino Acids
- Hormones, Carbon Dioxide, Urea
GACHU
How are red blood cells adapted for their function?
- Have a bioconcave disc shape, increases surface area to absorb and release oxygen
- Don’t have a nucleus, frees up space for more haemoglobin so they can carry more oxygen
- They contain haemoglobin (which contains lots of iron), haemoglobin reacts with oxygen to form oxyhaemoglobin
What are the 2 types of white blood cells + explain what their role is
- Phagocytes
- Lymphocytes
How do phagocyte
Detect things that are foreign in the body and then engulf the pathogen and digest them
How do lymphocytes work + explain memory cells
- Recognise antigens (every pathogen has a unique molecule called antigen)
- Produce antibodies (proteins) which destroys pathogens by:
- Labeling the pathogen so it’s easily recognisable by phagocytes
How do vaccinations work
- Vaccinations involve injecting dead pathogens into the body which carry antigens
- They trigger an immune response; your lymphocytes produce antibodies
- Memory cells will be produced, if those same pathogens infect you, antibodies to kill them will be produced much quicker and in a larger quantity
Pulmonary is for…
Hepatic is for…
Renal is for…
Veins
Artieries
- Lungs
- Liver
- Renal
- Bring blood to the heart
- Take blood away from the heart
How is oxygenated blood sent to the body
- Oxygenated blood is brought from the lungs to the pulmonary vein
- To the left atrium, contracts and forces blood into left ventricle
- Left ventricle contracts, pumping the blood around the body via the aorta
How is deoxygenated blood brought from the body
- Deoxygenated blood is brought from the body to the heart by the vena cava
- Takes blood into the right atrium, contracts and forces blood into the right ventricle
- Right ventricle contracts and pumps blood to the lungs via the pulmonary artery
How does the heart rate change during exercise?
- When you exercise, you produce more CO2 bc muscles are respiring more
- High levels of CO2 in blood is detected by the receptors in the aorta and carotid artery (artery in the neck)
- This sends impulses to the brain, brain sends signla to heart causing it to contract more frequently
How does the heart rate change under the influence of adrenaline?
*
What are some factors that can lead to coronary heart disease
- Having a diet high in saturated fat
- Smoking
- Being inactive
- High blood pressure
How are the arteries adapted for its function
- It has a narrow lumen, blood will be forced through at high pressures
- Thich muscle walls; walls of the artery should be thick to withstand high pressure
- Elastic fibre walls; to allow arteries to expand
How are veins adapted for its function
- It has a wider lumen, blood flows at much lower pressure
- Therefore the walls don’t need to be as thick
- They have valves which prevents the backflow of blood
How are capillaries adapted for its function
- Capillaries are one cell thick to enable a very short diffusion distance
What is excretion
Removal of waste products of metabolism
What are the excretory products of the body
- Urea in the kidneys
- Carbon Dioxide from the lungs
- Sweat from the skin
What are auxins
Auxins are plant hormones
Why do plant grow towards the light
- When a shoot is exposed to light, the auxin accumulates on the side that’s more shaded
- Makes the cells elongate and shoot bends towards light
What’s the difference between hormonal and nervous communication
- Hormonal: Chemicals that travel in your blood
- Slower messages
- Responses are long lived
- They act in a more general area
- Nervous: Invloves the use of electrical impulses
- Much faster message
- The electrical impulses will act on a specific area
- Responses are short lived
How does the CNS coordinate information
- The stimulus (a book) is detected by the receptors
- They send electrical impulses along the sensory neuron to the CNS
- Electrical impulses then pass along to the motor neuron to the effector
What does the CNS consist of
Brain and Spinal Cord
What is a synapse
- The connection between 2 neurons, this is where a neurotransmitter is released
- The nerve signals are transferred by chemicals called neurotransmitter which diffuses across the gap
How does a reflec arc work
- The receptor detects the stimulus (fire)
- Electrical impulses are then sent along the sensory neurons to the CNS
- In the CNS the sensory neurons pass the electrical impulses to the relat neuron
- The relay neuron relays the impulses to the motor neuron, which travel along the moto neuron the effector
- Muscle then contracts and moves hand away from fire
What happens to the eye when focusing on distant objects
- Ciliary muscles relax
