P1 4.1.1 Cell structure (will come up) Flashcards
What do plant cells contain? (eukaryotic)
Cell wall, cell membrane, cytoplasm, nucleus, vacuole, mitochondria. chloroplasts, ribosomes
What do animal cells contain (eukaryotic)
Cell membrane, cytoplasm, nucleus, mitochondria, ribosomes
Relative size of of bacterial cells (prokaryotic cells)
0.2-2 micrometres (μm)
What do prokaryotic cells contain
Slime capsule, cell wall, cell membrane, cytoplasm, dna loop, flagella, plasmids, ribosomes
How is the nucleus related to its function
Contains genetic material, including DNA.
Controls the cells activities
How is the cell membrane related to its function
It controls the movement of substances in and out of the cell.
Holds the cell together
How are mitochondria related to their function
Where reactions for aerobic respiration take place
How is the cell wall related to its function
Supports and strengthens the cell (made of cellulose)
How are chloroplasts related to their function
Where photosynthesis occurs. They contain a green substance called chlorophyll which absorbs the light needed for photosynthesis
How are plasmids related to their function
Small closed rings of DNA
How are sperm cells specialised for their function
A long tail to help it swim towards the egg, lots of mitochondria which provide energy for swimming from respiration, enzymes in the head to digest through the egg cell membrane
How are nerve cells specialised for their function
They are long to cover more distance, have branched connections at their ends to connect to other nerve cells and form a network throughout the body
How are muscle cells specialised for their function
The cells are long so they have space to contract, contain lots of mitochondria to transfer the energy needed for contraction
How are root hair cells specialised for their functions
They give the plant a big surface area for absorbing water and mineral ions from the soil
How are xylem specialised for their function
They are hollow in the centre, they form a continuous hollow tube of dead cells by losing their end walls
How are phloem specialised for their function
They have very few subcellular structures so substances can flow through them
Small pores in end walls to allow the flow of cell sap
What is cell differentiation
The process by which a cell changes to become specialised for its job.
As cells change they develop different subcellular structures and turn into different types of cells
What do the phloem do
They transport the products of photosynthesis (sugars)
What is the function of cytoplasm
Where chemical reactions happen
Contains enzymes that control these reactions
What is the function of ribosomes
Where proteins are made in the cell
Function of a vacuole
Contains cell sap, a weak solution of sugar and salt
Keep the cell turgid
When do animal cells differentiate
At an early stage
embryo
When do plant cells differentiate
Throughout their whole life
What is cell division for in mature animals
Repair and replacement
Differences between light and electron microscopes
Electron microscopes have a much higher magnification
Electron microscopes have a higher resolution
Advantages of electron microscopes
You can see much smaller things in more detail such as subcellular structures eg ribosomes and plasmids
Formula for magnification
Magnification = image size / real size
How do bacteria multiply and how often
By binary fission
Every 20 minutes
What is binary fission effected by
Temperature and the availability of nutrients (warm and lots of nutrients is ideal)
Why must petri dishes and culture media be sterilised
To prevent contamination by unwanted microorganisms as they will affect your results and potentially result in the growth of pathogens
How to sterilise inoculating loops
Pass them through a hot flame
How should the petri dish be stored and why
With the lid lightly taped on - to stop microorganisms from the air getting in
It should be stored upside down - to stop drops of condensation falling onto the agar surface
