Cell Structure Flashcards
What is the magnification of the electron microscope?
250,000 +
Describe the electron microscope.
- Shows ultrastructure
- Produces very clear images
- Uses electrons instead of light
How many types of electron microscope are they?
Two
What does the Transmission Electron Microscope (TEM) show?
Shows internal structures.
What does the scanning electron microscope (SEM) show?
Shows the surface.
What is ultrastructure?
Is the fine detail of a cell as seen with an electron microscope.
What is cytoplasm?
- Jelly like liquid
- Surrounds the nucleus
- Organelles eg. mitochondria, chloroplasts, ribosomes are suspended in the cytoplasm.
- Most reactions in a cell take place in the cytoplasm.
What is protoplasm?
The cytoplasm + the nucleus
What is the role of the mitochondria?
To supply energy to the cell
Where does respiration take place in the cell?
Mitochondria
What part of the mitochondria produce energy?
The inner membranes, the infoldings
Does the number of folds affect the amount of energy produced in mitochondria?
- Yes
- The more folds a mitochondrion has, the more energy it produces.
What are ribosomes?
- Tiny, bead like structures
- Made of RNA and Protein
What is the function of ribosomes?
To make proteins
What are chloroplasts?
- Green structures
- Contain the green pigment chlorophyll
What is the function of chloroplasts?
- To facilitate photosynthesis
- Photosynthesis takes place in chloroplasts.
What cells have cell walls?
Any plant cell
Describe cell walls.
- The cell wall is rigid and give plant cells a very defined shape
- Composed of cellulose
- Permeable
What does permeable mean?
All molecules can pass in through cell walls
What is the function of cell walls?
To support and strengthen the cell
What are vacuoles?
Are membrane-bound sacs within the cytoplasm of a cell
What is the function of vacuoles?
To provide structural support, as well as serving functions such as storage, waste disposal, protection and growth
Do plant cells have large vacuoles?
Yes
What are eukaryotes?
Have membrane enclosed nucleus and cell organelles
eg. plant and animal cells
What are prokaryotes?
- Do not have an nucleus or membrane enclosed organelles
- Single celled, eg. bacteria
What are cell membranes made up of?
Phospholipids and proteins.
Name four functions of cell membranes.
- Separate the cell organelles and cytoplasm form the outside
- Controls what enters and leaves the cell
- Membranes give support to the cell
- Membranes recognise molecules that touch them.
Where is the nucleus located?
In the centre of the cell
What is the nucleus?
The control of the cell
What do nuclear pores do?
- Control entry and exit of molecules in and out of the nucleus
- Allows messenger RNA (mRNA) to pass in and out of the nucleus.
Definition of protoplasm.
Is all the living parts of the cell
Definition of cytoplasm.
Is the living material in a cell outside the nucleus
What is chromatin?
Name given to chromosomes when they are elongated and not dividing
Name some distances between plant and animal cells.
Plant Cells -Have a cell wall -Have a large vacuole -Have chloroplasts Animal Cells -Do not have a cell wall -Do not have a large vacuole -Do not have chloroplasts
