Paper 2 Flashcards
What is the function of red and white blood cells?
RED = carrying oxygen WHITE = defending from disease
What is cell differentiation?
The process by which a cell changes to become specialised for a job.
What is an undifferentiated cell?
A stem cell - it can multiply and differentiate (turn in to) different cells depending on the instructions given.
Why are doctors excited by stem cells? (further)
They have potential to turn into any type of cell which brings great possibilities for research and development.
Where can undifferentiated cells be found?
In feutus’
Where can adult stem cells be found?
Bone marrow
What is the difference between embryonic stem cells and adult stem cells?
Embryonic stem cells can be differentiated into any cell, adult stem cells can only turn into certain cells, such as red blood cells.
Why are some people against stem cell research? and what is the counter argument for this point?
They feel human embryo’s should not be used for research as every one is a potential human life.
Counter Argument - People who are suffering great deals of pain need these stem cells
How are adult stem cells used in medicine today?
Stem cells are transferred from the bone marrow of a healthy person to a patient who cannot produce their own blood cells.
What is a potential use for embryonic cells in medicine?
Nerve cells for those paralysed by spinal injuries
What risks are there for using stem cells in medicine?
Cells grown in a lab may become contaminated with a virus and passed on to the human.
What is a root hair cell?
The cells on the plant root grow into long ‘hairs’ which stick out in the soil. Each branch of ‘hair’ is covered in millions of root hair cells.
What process’ does a root hair cell use to absorb water?
Osmosis - higher concentration of water in the soil than in the cell.
Active Transport - Dissolve mineral ions from the soil.
What are the main 4 factors affecting transpiration rates?
- Light Intensity
- Temperature
- Wind Speed
- Humidity
What is transpiration?
The loss of water from a plant through the stomatal pores.
What processes cause transpiration?
evaporation and diffusion
What can be used to measure transpiration rates?
Potometer
When does photosynthesis occur?
In the day or in synthetic lightning.
What gases are taken in and given out hen a plant respires?
Oxygen is taken in and Carbon Dioxide comes out, just like humans
How are leaves adapted for diffusion?
- Broad, so there’s a large surface area for diffusion.
- Thin, this provides a short distance for diffusion.
- Air spaces, gases can move between cells easily.
- Stomata, allow gases in and out (and water out).
- Stomatal opening and closing caused by guard cells
How do guard cells change the stomatal opening?
By changing their own shape and volume - as guard cells increase in volume they open stomata. When guard cells decrease in volume they close stomata.
What are platelets?
Small fragments in the blood (that help blood to clot).
What is the function of platelets?
Platelets prevent blood loss by forming clots at the damaged area.
What holds platelets together at a blood clot?
A mesh of a protein called fibrin.
Name a disease that you may be vaccinated for?
Polio or Measles
How do vaccinations work?
Dead pathogens are inserted into the body. They are harmless but still contain antigens. This triggers an immune response and the lymphocytes produce antibodies to kill them. Memory cells are produced and remain in the bloodstream for a long period of time.
What are the tree main roles of the kidneys?
1 - Removal of urea from the blood.
2 - Adjusting salt ion levels in the blood.
3 - Adjusting water content in the blood.
How is urea formed?
Urea is formed in the liver from excess amino acids.
What is a nephron?
A filtration unit in the kidney. There are thousands of them inside each kidney.
What happens at each of the three stages in the nephron?
1 - Ultrafiltration
2 - Reabsorbtion
3 - Release of waste
What is ultrafiltration in the nephron
Blood from the renal artery flows along the glomerulus at the start of the nephron.
The high pressure squeezes water, urea, ions and glucose out of the blood into the bowman’s capsule.
Big molecules like proteins cannot fit through gaps in the membrane, so they stay in the blood.
What is the glomerulus?
A bundle of capillaries at the start of the nephron.
What is the glomerular filtrate?
The liquid and molecules in the Bowman’s capsule.
What is reabsorbtion?
As filtrate flows along the nephron, useful substances are selectively reabsorbed back into the blood.
Which substances are selectively reabsorbed back into the blood?
- All the glucose
- Sufficient ions
- Sufficient water
Which substances are ultrafiltrated into the bowman’s capsule?
- water
- urea
- glucose
- ions
Where is all the glucose reabsorbed into the blood?
The proximal convoluted tube
What process see glucose reabsorbed into the blood?
Active transport
Where is sufficient water reabsorbed from to get into the blood through osmosis?
The collecting duct
What substances remain in the urine at the end of the nephron?
- Water
- Urea
- Ions
Where does urine go after it leaves the kidneys?
Through the ureter and down to the bladder before being released through the urethra.
What affect does ADH have on the body and how is this affect achieved?
ADH makes more water absorb back into the blood, this happens as the ADH makes the collecting duct more permeable so more water escapes it.
What is the name for ADH?
Anti-Diuretic Hormone
What three main ways are water/fluids lost?
Sweating
Breathing
Weeing (Urinating)
What is negative feedback?
When something is wrong a mechanism is triggered to bring it back to normal.
How is water level controlled by negative feedback?
Water gain = detected > less ADH > less absorption.
Water loss = detected > more ADH > more absorption.
Where is the pituitary gland?
In the brain.
Which hormones are produced in the pituitary gland?
ADH, FSH and LH
What are the effects of LH on the body?
Stimulates the release of an egg from an ovary
What are the effects of FSH on the body?
Causes an egg to mature in an ovary.
Stimulates the Ovaries to produce oestrogen.
Where is FSH produced?
Pituitary gland
Where is LH produced?
Pituitary gland
What does LH stand for? H
luteinizing hormone
What does FSH stand for? H
Follicle Stimulating Hormone
Define biodiversity:
Biodiversity is the variety of different species of organisms on Earth, or within an ecosystem.
What are the dimensions of a quadrant?
1m x 1m
What is DNA?
A long list of instructions on how to put an organism together and make it work
What are the complimentary DNA bases?
A - T
C - G
What are the four DNA bases?
Adenine
Thymine
Cytosine
Guanine
What shape is a DNA molecule?
Two strands coiled into a Double-Helix
Held together by chemical bases
