1. Cell Structure Flashcards
Two types of cells
Prokaryotic and eukaryotic
Prokaryotic cells
Single celled organisms (bacteria)
Eukaryotic cells
Multicellular organisms (plants and animals)
Plasma membrane
Found on the surface of animal cells plant cells and prokaryotic cells
Made from lipids and protein
Function: regulates the movement of substances in and out of the cell
Cell wall
Found in plant cells
Rigid structure made from cellulose
Function: support
Nucleus
Surrounded by a nuclear envelope, which is a double membrane, containing many pores. Nucleolus inside nucleus. Contains chromatin.
 function: controls the cells activities (transcription), DNA contains instructions to make proteins and the pores allows substances to move between nucleus and cytoplasm.

Nucleolus
Found in the nucleus
Function: make ribosomes
Lysosome
Contains digestive enzymes
Function: can be used to digest invading cells
Ribosome
Made from proteins and RNA
Function: site where proteins are made
Rough endoplasmic reticulum
System of membrane is covered with ribosomes
Function: fold and process proteins that have been made by ribosomes
Smooth endoplasmic reticulum
System of membranes without ribosomes
Function: synthesise and process lipids
Vesicle
Can be formed by the Golgi and ER or the cell surface
Function: transport substances in and out of the cell and between organelles
Golgi apparatus
Function: process and package new lipids and proteins and make lysosomes
Mitochondrion
Double membrane in a membrane is folded to form cristae. Inside is the matrix which contains enzymes involved in respiration. Require a lot of energy
Function: site of aerobic respiration where ATP is produced
Chloroplast
Double membrane has internal membranes (thylakoid membranes). These are stacked up in some parts to form grana. Grana and thylakoid membrane is linked together by lamellae.
Contains chlorophyll which absorbs light for photosynthesis
Function: site of photosynthesis. Some parts of photosynthesis happen in the grana and other parts in the stroma
Centriole
Made from microtubules, found in animal cells and some plant cells
Function: separation of chromosomes
Cilia
Hair-like structures
Function: movement of substances along the cell surface
Flagellum
9+2 formation
Function: movement
Protein production
Proteins are made at ribosomes
Ribosomes on the rough endoplasmic reticulum make proteins that are attached to the cell membrane. The ribosomes in the cytoplasm make proteins that stay in the cytoplasm
Proteins produced at the RER are folded and processed then transported to the Golgi apparatus and vesicles. Processed further
Proteins go into more vesicles to be transported around the cell
Cytoskeleton
Network of protein threads arranged as microfilaments and microtubules
Functions: support organelles keeping them in position, strengthen the cell, movement of materials within the cell, allow the cell to move.
Prokaryotic DNA vs eukaryotic DNA
Circular vs linear
Size of prokaryotes
Less than two micrometres diameter
Size of eukaryotes
10 to 100 micrometres diameter
What is the cell wall made out of in prokaryotes?
Polysaccharide
What is the cell wall made out of in eukaryotes?
Cellulose or chitin
Light microscopes
Use light
Small resolution (0.2 micro metres)
Maximum magnification x1500
Laser scanning confocal microscope
Use laser beams with fluorescent dye
Attached to a computer to generate an image can be 3D.
Can be used to look at different depths. 
2 types of electron microscopes.
Transmission and scanning.
Transmission electron microscope.
Use electromagnets to focus a beam of electrons.
Denser parts absorb more electrons.
High resolution (0.0002 micrometers).
Magnification - x1,000,000 and can be more.
Can only be used on thin specimens.
Scanning electron microscope.
Beam of electrons across specimen.
Shows the surface of the specimen and can be 3D.
Lower resolution than TEM (0.002 micrometres)
Magnification - less than 500,000
Staining for light microscopes.
Using dye.
Different dyes make different things show up.
Specific dyes and their uses.
Eosin - cytoplasm.
Methylene blue - DNA.
Staining for electron microscopes.
Dipped in solutions of heavy metals (lead).
Preparing a microscope slide.
Take a thin slice.
Use tweezers to put it into the middle of the slide.
Use a cover slip.
You can also wet mount using a drop of water.
Using a light microscope.
Put the slide on the stage.
Select the lowest powered objective lens.
Use the coarse adjustment knob to move the stage.
Look down the eyepiece lens and use the coarse adjustment knob to focus the image.
Use the fine adjustment knob to get a clear image.
Move to a higher powered objective lens.
Eyepiece graticule.
Fitted to the eyepiece.
Has numbers but no units.
Stage micrometer.
Microscope slide placed on the stage.
Accurate scale with units.
Used to calculate the value of the divisions in the eyepiece graticule at a particular magnification.
Measure the size of the specimen.
Stroma.
Contains enzymes to aid photosynthesis
Contain starch grains for an energy store
