B1. Cells, microscope and specialised cells Flashcards
What is the function of the cell wall?
The outer layer of a plant cell, gives strength and supprt
What is the function of the nucleus?
- Controls the cell - Contains the genetic information called DNA
What is the function of the cell membrane?
Controls what enters and leaves the cell
What is the function of ribosomes?
Site of protein synthesis
What is the function of mitochondria?
Site of respiration (release of energy from food)
What is the function of chloroplast?
Contains chlorophyll, site of photosynthesis
What is the function of the large permanent vacuole?
Stores cell sap
In which type of cell would you find a cell wall?
Plant cell only
In which type of cell would you find ribsomes
Both animal and plant cells have ribosomes
Name 2 differences between plant cells and animal cells
Plant cells have a cell wall and chloroplasts whereas an animal cell does not.
What part of the animal cell is labelled A in the diagram?
Nucleus
What part of the animal cell is labelled B in the diagram?
Cytoplasm
What part of the animal cell is labelled C in the diagram?
Cell membrane
What part of the animal cell is labelled D in the diagram?
Mitochondrion
The diagram shows an unlablled plant cell. What is label A?
Cellulose cell wall
The diagram shows an unlablled plant cell. What is label B?
Chloroplasts
The diagram shows an unlablled plant cell. What is label C?
Large permanent vacuole
The diagram shows an unlablled plant cell. What is label D?
Nucleus
The diagram shows an unlablled plant cell. What is label E?
Cytoplasm
The diagram shows an unlablled plant cell. What is label F?
Cell membrane
The diagram shows an unlablled plant cell. What is label G?
Mitochondria
How do you calculate total magnification
Total magnification = Eyepiece lens x objective lens
Define the term resolution
Resolution is the ability to distinguish between two separate points in an image
Define the word ‘magnification’
Magnification is how much bigger an image is compared to it’s actual size. Can be calculated by using the IAM triangle.
What type of microscope could be used for viewing for small organelles e.g. ribosomes?
Electron microscope
What type of DNA do prokaryotic cells have?
1 circular chromosome, NOT enclosed by a nucleus.
What type of DNA do eukaryotic cells have?
Many linear chromosomes enclosed by a nucleus.
How are sperm cells adapted for their function?
● Streamlined head and long tail to aid swimming. ● Many mitochondria (where respiration happens) which supply the energy to allow the cell to move. ● The acrosome (top of the head) has digestive enzymes which break down the outer layers of membrane of the egg cell.
How are nerve cells adapted for their function?
● The axon is long, enabling the impulses to be carried along long distances ● Having lots of extensions from the cell body (called dendrites) means branched connections can form with other nerve cells ● The nerve endings have many mitochondria which supply the energy to make special transmitter chemicals called neurotransmitters. These allow the impulse to be passed from one cell to another.
How are muscle cells adapted for their function?
● Special proteins slide over each other, causing the muscle to contract ● Lots of mitochondria to provide energy from respiration for contraction ● They can store a chemical called glycogen that is used in respiration by mitochondria.
How are root hair cells adapted for their function?
● Have a large surface area due to root hairs, meaning more water can be absorbed by osmosis. ● The large permanent vacuole affects the speed of movement of water from the soil to the cell. ● Have mitochondria to provide energy from respiration for the active transport of mineral ions into the root hair cell.
How are xylem cells adapted for their function?
● Xylem cells hollow and are joined end-to-end to form a continuous tube so water and mineral ions can move through. ● Lignin is deposited in spirals which helps the cell walls which help withstand the pressure from the movement of water.
How are phloem cells adapted for their function?
● Cell walls of each phloem cell form structures called sieve plates when they break down, allowing the movement of substances from cell to cell. ● Have few organelles so food can move faster. ● Have a companion cell with mitochondria to supply energy.
What is the function of sperm cells?
Sperm cells contain a nucleus with half the DNA (23 chromosomes). Sperm cells fertilise the egg cell during sexual reproduction.
What is the function of nerve cells?
Transmits electrical impulses.
What is the function of muscle cells?
They are specialised to absorb water by osmosis and mineral ions by active transport from the soil.
What is the function of xylem cells in a plant?
They are specialised to transport water and mineral ions up the plant from the roots to the shoots.
What is the function of phloem cells in a plant?
Transports food (by translocation) from the leaves to other parts of the plant.
How do you convert mm to μm?
x1000
Convert 35mm into μm
35mm x 1000 = 35,000μm
Convert 4.7mm to μm
4.7 x 1000 = 4700μm
Name 2 difference between prokaryotic cells and eukaryotic cells.
- Prokaryotic cells do not have a nucleus, eukaryotic cells do.
- Prokaryotic cells do not have any membrane bound ribosomes, eukaryotic cells do.
- Prokaryotic cells have smaller ribosomes to those in eukaryotic cells.
