B1 Flashcards
What does the nucleus do?
Controls activities of the cell
Contains organism’s genetic material
Determines cell’s appearance and function
Contains instructions to make new cells or organisms
What does the mitochondria do?
Where respiration happens
Enzymes enable glucose and oxygen to react together to transfer viral energy to the organism
What is the cell membrane?
A barrier that controls which substances enter and leave the cell
What is the cell wall?
It surrounds the cell and is made of cellulose
Makes the wall rigid and supports the cell
What is the chloroplast?
Contains green chlorophyll
This transfers energy from the sun to the plant which is used in photosynthesis
Chloroplasts are only in the green parts of the cell
What is the vacuole?
Full of cell sap
Water solution of sugar and salts
Helps keep the cell rigid
Supports the plant and keeping it upright
What does an animal cell contain?
Nucleus
Mitochondria
Cytoplasm
Cell membrane
What does a plant cell contain?
Everything is an animal cell as well as
Vacuole
Cell wall
Chloroplasts
What does a prokaryotic cell contain?
Cell wall
Genetic material
Cytoplasm
Cell membrane
A bacterial chromosome which is usually circular
What features do bacterial cells contain?
Flagella
Pili
Slime capsule
Plasmid
What is the flagella and what does it do?
‘Tail-like’ structures that allow the cell to move through liquids
What are pili and what do they do?
Tiny ‘hairlike’ structures that enable the cell to attach to structures
Also used to transfer genetic material between bacteria.
What is the slime capsule and what does it do?
Layer outside the cell wall
Protects bacterium from drying out and from poisonous substances
Helps bacteria stick to smooth substances
What is a plasmid and what does it do?
A circular piece of DNA that is used to store extra genes
Those genes are not needed for the bacterium’s survival but may help in times of stress
As an example, this is where antibiotic resistance genes are normally found
What is the equation for total magnification?
Eyepiece lens magnification x objective lens magnification
What is used to identify the nucleus of an animal cell?
Methylene blue
What is used to identify the nucleus of a plant cell?
Iodine solution
What is used to identify bacterial wall cells?
Crystal violet and it stains them
What does a light microscope contain?
Eyepiece lens
Objective lens
Coarse focus
Fine focus
Stage
Slide
Light/mirror
What are the two types of electron microscopy?
Transmission electron microscopes (TEM)
Scanning electron microscope (SEM)
What does a TEM do?
Produce the most magnified image
Uses a beam of electrons to pass through a thin slice of the sample producing a 2D image
What does an SEM do?
Produces a 3D imagine of a surface
They send a beam of electrons across the surface of a specimen. The reflected electrons are collected to produce an image
What does an electron microscope contain from top to bottom?
Electron source
Electron beam
Specimen
Electromagnetic lenses
Viewing screen
What are the advantages and disadvantages of a light microscope?
Cheap to buy and operate
Small and portable
Simpler to prepare a sample
Natural colour is seen (unless staining is used)
Specimens can be alive or dead
What are the advantages and disadvantages of an electron microscope?
Expensive to buy and operate
Large and more difficult to move
Sample preparation is complex
Black and white images produced
Specimens have to be dead
Better magnification that an electron microscope
What is a chromosome?
A molecule of DNA