B1 Flashcards
What is the function of the chloroplast
Where photosynthesis takes place, providing food for the plant
What is the function of the vacuole
Contains cell sap and is where the cell stores water
size of image =
magnification * size of object
What is made out of cellulose
Cell wall
what is the maximum magnification and resolution a light microscope can have?
magnification - x2000
resolving power - 200nm
if the image is blurry do we turn the coarse or fine focus wheel
coarse
what does the coarse focus wheel do
allows for quick focusing by moving the objective lens or stage up and down - initial focusing
what does the fine focus wheel do
sharpen the focus quality of the image
1 micrometre is 1 x 10^-6 m. what is 0.0008cm in micrometres
8 micrometres
suggest why there are many more mitochondria in muscle cells than in skin cells
muscles are used most of the time. this means that muscles, and therefore muscle cells will require more energy than skin cells. since skin cells are not always using energy. mitochondria provides the energy using aerobic respiration so more wil be needed in a muscle cell
what is diffusion
the movement of a substance from an area of high concentration to an area of lower concentration
what is osmosis
the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a partially permeable membrane
what is active transport
the movement of particles from an area of low concentration to an area of high concentration against the concentration gradient
give an example of where active transport takes place
root hairs or in the gut
give an example where osmosis takes place
Movement of salt-water in animal cell across our cell membrane
give me an example of where diffusion takes place
oxygen/carbon dioxide exchange, urea
what is a hypertonic solution
one that contains more solute
what is a hypotonic solution
one where there is more solvent
what is an isotonic solution
contain equal concentrations of impermeable solutes on either side of the membrane
what is turgor
Pressure exerted by fluid in a cell that presses the cell membrane against the cell wall. it’s what makes the leaves and stems of a plant rigid
what is plasmolysis
where the cell membrane moves away from the wall due to too much water moving out of the cell and the external solution is less dilute
give one use of sugar in the body
it can be broken down into glucose for aerobic respiration and anaerobic respiration for energy
explain how villi are adapted for efficient absorption of sugar molecules
- cell membrane is one cell thick which allows the rate of diffusion to be increase as the sugar molecules do not need to travel very far
- there are many microvilli which increases the surface area
what is a prokaryotic cell
a single celled organism that lacks a nucleus
what is an eukaryotic cell
any cell or organism that possesses a clearly defined nucleus
explain how a student could modify their investigation to determine the concentration of the solution inside each [egg]
use five or more different concentrations of salt/sugar solutions in the beakers. plot the percentage change (mass/volume) on a graph. plot a line of best fit and find the concentration of the egg by looking at 0% change.
mass before - 73.5 70.3, 72.4, 71.6, 70.5
mass after - 77.0, 73.9, 75.7, 73.1, 73.8
a student said the result for egg 4 was anomalous. do you agree?
yes because the mass change is much lower than the other results
WORK IT OUT AMY
what is the role of the mitochondria
Mitochondria are the site of aerobic respiration, so they release energy for the cell
Which of the following are included in the ‘5 kingdoms of life’
Plants
Bacteria
Fungi
Animals
Protoctists
what does heterotrophs mean
animals need to get their energy from other organisms
what is differentiation
the process by which a cell changes to become specialised
what does autrotrophs mean
they get their energy from the sun
State and explain features that most exchange surfaces have in common.
Feature 1 - Large surface area
Explanation 1 - Lots of molecules can diffuse across at the same time
Feature 2 - Surfaces are very thin
Explanation 2 - Substances only have to diffuse a short distance
Feature 3 - Surfaces are permeable
Explanation 3 - Substances are able to pass through the surface
Feature 4 - Good blood supply (good supply of ‘internal medium’)
Explanation 4 - Maintains a strong concentration gradient as blood is constantly replaced
Feature 5 - Good supply of ‘external medium’
Explanation 5 - Maintains a strong concentration gradient as the air or food etc is constantly replaced
Which adaptation in plants contributes to the efficient exchange of gases?
The flattened shape of their leaves
name the two types of stem cells found in animals
adult stem cells and embryonic stem cells
