biology Flashcards
(17 cards)
What structures are found in plant cells but not animal cells
Cell wall, chloroplast, a large vacuole
Name the 3 different magnifications of the objective lens
X4, X10, X40
How do you calculate total magnification
eyepiece lens magnification X objective lens magnification = totsl magnification
Properties of a light microscope
Magnification can be x2000 (2 thousand); Uses a beam of light to form an object; Cheaper than electron microscope; Can put living or dead specimens in
Properties of a electron microscope
Uses a beam of electrons to form an object; Magnification can be X2,000,000 (2 million); Can only put a dead specimen in; They are large and expensive; Must be kept in controlled environments such as labs
What is an Eukaryotes cell
A cell with a nucleus. So all cells with a nucleus are said to be eukaryotic.
What is a Probaryotic cell
A cell that doesn’t have a nucleus - usually a bacteria cell
What do plant cells have that animal cells do not
Cell wall; Chloroplast; Large Vacuole
What does a bacteria cell have that plant and animal cells do not
A single loop of DNA/ Plasmid; Slime capsule
What are the adaptions of alveoli and villi
Paragraph surface to volume ratio possible question
Because humans have a low surface to volume ratio we need specialised exchange surfaces to increase it. The lungs have millions of alveoli which together gives a large surface area which we can use to absorb oxygen. This is the same with villi in the intestines which have a massive surface area to absorb nutrient
What is active transport
The movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration. It alwyas takes place across a membrane and requires energy from cellular respiration.
Example of active transport
A plant needs to absorb water and mineral ions from the soil to survive. The ions are moved via active transport from the soil (which is a region of lower concentration) to the root hair cells (which is a region of higher concentration)
What is cellular respiration
It is responsible for energy that the cell uses. The mitochondria breaks down glucose to release energy. The ATP stores the enrgy and takes it to the part of the cells that need it
What is a specific adaptation of villi and alveoli
If it says give 2 examples of villi and alveoli adaptations
- Large surface areas to absorb proteins
- Short Diffusion Distance: The villi walls are only one cell thick, ensuring that nutrients don’t have to travel far to enter the bloodstream.
What is the definition of osmosis?
The movement of water molecules down a water potential gradient from a higher water potential to a lower water potential Through a partically permeable membrane
Converting between units
- 1 km (kilometre) = 1000 m (metres)
- 1 m = 100 cm (centimetre)
- 1 cm = 10 mm (millimetres)
- 1 mm = 1000 μm (micrometres)
- 1 μm = 1000 nm (nanometre)
What does IAM mean and how does it work?
I = Image size
A = Actual size
M = magnification
I = A x M
A = I/M
M = I/A
