b1

Created by

scarlett macfarlane

Cards (52)

State the equation to calculate magnification.
Magnification =image/actual size.
Which objective lens should you use first to observe slides?
The lowest powered objective lens.
Describe how to draw a biological specimen.
Use a sharp pencil, use continuous lines with no shading.
What is cell differentiation?
The process by which a cell changes to become specialised for a job.
What does the nucleus contain?
Chromosomes made of DNA.
How many chromosomes do human cells contain?
23 pairs.
What are the stages of the cell cycle?
Growth of organelles and DNA replication, mitosis, cell splitting and new cell membranes forming.
Why do cells undergo mitosis? 
Grow and replace cells that have been damaged.
What does mitosis produce?
Two identical cells.
What are stem cells?
Cells that have not yet differentiated or become specialised.
What are the main sources of stem cells?
Human embryos and adult stem cells from bone marrow.
What can stem cells be used for?
Replace faulty blood cells, producing nerve cells to treat paralysis and therapeutic cloning to form organs.
Why are some people against using embryonic stem cells?
They are seen as a potential human life that is destroyed.
Where are stem cells found in plants?
In the meristem of roots and shoots where growth occurs.
State five cell parts found in both plants and animals cells
Cytoplasm, cell membrane, nucleus, mitochondria and ribosomes.
State 3 parts found in plant cells but not animal cells.
Chloroplasts, permanent vacuole and cell wall.
List 5 specialised animal cells.
Sperm, muscle, nerve, red blood cell and white blood cell.
List 4 specialised plant cells.
Root hair cell, xylem, phloem and palisade cell.
Define a eukaryotic cell.
Complex cells that have a nucleus.
Define a prokaryotic cell. 
A smaller and simpler cell with no nucleus (e.g. a bacteria).
Bacterial cells contain what parts?
Cell membrane, cell wall, no nucleus (they have strands of DNA and plasmids).
What is a plasmid? 
A ring of DNA often found in bacterial cells.
What is the role of mitochondria?
They are the site of aerobic respiration and they release energy.
What is the role of ribosomes?
Synthesize proteins.
What is the function of chloroplasts?
Where photosynthesis occurs.
What is the definition of magnification?
How many times larger an image is than it is in real life.
Define the term resolution of a microscope. 
The ability of a microscope to see detail and to distinguish two points as two separate points.
Can you see ribosomes with a light microscope?
No they are too small.
Define the term diffusion. 
The spreading out of particles from an area of high concentration to an area of low concentration.
What states of matter does diffusion happen in?
Liquids and gases.
What factors will speed up diffusion?
A large concentration gradient and higher temperatures
What is the role of cell membranes?
To let substances in and out of cells.
Define the term osmosis. 
The movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
What happens if you place cells in pure water?
The cells take in water by osmosis and swell.
Define the term active transport. 
The movement of particles from low concentration to high concentration. The process requires energy.
Where does active transport occur in plants?
In the root hair cells when they take in minerals from the soil.
Where does active transport occur in humans?
In the small intestine when they absorb glucose into the blood.
What features make an efficient exchange surface?
A large surface area to volume ration, thin with a short diffusion pathway.
Where does gas exchange occur in the lungs?
In the alveoli.
How are the small intestine adapted for diffusion?
They have villi to increase surface area and have a good blood supply.