What does a nucleus do in a cell?
It controls the cell's activities and contains the genetic material for cellular reproduction.
What is the function of cytoplasm?
It's where most of the chemical reactions take place in a cell
What does the cell membrane do?
It controls what comes in and goes out of a cell.
What do mitochondria do?
Sub-cellular structures where aerobic respiration takes place
What do ribosomes do?
Ribosomes synthesise proteins
What is a cell wall made of?
Cell walls are plants' cells - they are made of cellulose to strengthen the cell.
What is the function of chloroplasts?
Chloroplasts - found in plant cells - make glucose (food) for the plant through photosynthesis.
Name the two main kinds of cell
Prokaryotic cells (bacterial) Eukaryotic cells (plant, animal, fungal)
What are some of the main differences between prokaryotic and eukaryotic cells?
Prokaryotic cells are: Smaller Genetic material is not in a nucleus Genetic material is in a single DNA loop and there may be one or more small rings of DNA called PLASMIDS They do not contain mitochondria or chloroplasts
What kind of shapes can bacteria have?
Spherical Spiral Rod Curved rod
What are flagella?
Tails on cells to move them around (e.g. sperm cells or bacteria)
Explain the nature of plasmids
They are loops of DNA found in bacteria. They can be transferred from one cell to another, allowing bacteria to pass genes around. They are also useful for scientists to insert genes into different bacteria.
Define 'resolution' in the context of microscopes
The ability to discern more than one object - e.g., cells can't be seen with the naked eye, but under a microscope, they begin to be 'resolved'.
What do electron microscopes do?
They pass electrons through a specimen being 'viewed' giving a much clearer image.
What is the formula for calculating magnification?
Magnification = size of image/size of real object
What sub cellular structure controls activities in the cell?
Nucleus
Where are proteins made in a cell?
On the ribosomes
Note three structures found in plant cells that are not found in animal cells
Cell wall Chloroplasts Permanent vacuole
What is the function of cell sap?
To support the cell
Where is DNA found in bacteria?
Floating plasmids
Arrange in order of size (largest to smallest) bacterium, liver cell, nucleus, ribosome
Liver cell Nucleus Bacterium Ribosome
What is a micrometre?
1x10-6(m)
What is an ecosystem
All the organisms living in a habitat and all the non-living parts of that habitat
So - snails and rocks!
polar bears and ice!
Define biological competition
Living species trying to get enough resources to survive
What is interdependence?
Different species relying on each other for food, shelter, pollnation, seed dispersal...
If one species is removed, it can affect the whole community.
Define abiotic
non-living
"a"- as a prefix means "without" in Greek
Define biotic
"Living"
bios in Greek means life.
Define four abiotic factors that affect living communities
light intensity
temperature
moisture levels
soil pH and mineral content
wind intensity and direction
C02 levels for plants
O2 levels for animals
Define three biotic factors that can affect a habitat
Changes in food availability
Change in number of predators
Introduction of pathogens/diseases
One species outcompeting another
