B1.1 - Cell structures Flashcards
What are Eukaryotic cells ? + Example
Cells whose genetic nuclei is contained within a nucleus.
e.g Animal cell, plant cell
What are Prokaryotic cells ? + Example
Cells whose genetic material floats within the cytoplasms.
e.g bacteria
Name all the organelles in an animal cell ?
- Nucleus
- Mitochndria
- Cytosplasm
- Cell membrane
Name the organelles found in plant cells?
- Nucleus
- Cell wall
- Cell membrane
- Chloroplast
- Mitochondria
- Vacuole
- Cytoplasm
what is the function of the nucleus ?
- Controls the cell, the activities in the cell
- Contains the organisms genetic material, arranged as chromosomes
- Determines cells appearance and function
What is the function of the mitochondria ?
-The ‘power-house’ of the cell.
- Provides energy by respiration
What is the function of the cell membrane?
- Holds the cell together
- Controls what goes in and out of the cell
- Delicate surface membrane made of two layers of phospholipid
What is the cytoplasm ?
Jelly-like substance
What is the function of the cytoplasm ?
- Transfers energy, makes things, and stores food.
- Jelly-like substance where hundreds of reactions take place, which make up metabolism/ keep the cell alive
Difference between Eukaryotic and Prokaryotic cells?
Eukaryotic : The cell type is complex and relatively large 10-100 μm
Prokaryotic cells : The cell type is simple and typically smaller ~1-10 μm
What does MRS GREN stand for ?
M = ovement
R = espiration
S = ensitivity
G = rowth
R = eproduction
E = xcretion
N = utrition
Which English inventor and scientist where discovered cells using his self-designed microscope in 1665?
Robert Hooke
Examples of Eukaryotic cells ?
Animal and plant cells
Examples of Prokaryotic cells ?
Bacterial cells
What are Ribosomes ?
Ribosomes are tiny granules on the membranes in the cytoplasm.
What is the function of ribosomes ?
Ribosomes are where proteins are made in the cell
What is the function of chloroplasts ?
- The chloroplasts contain green chlorophyll
- The chlorophyll transfers energy from the sun to the plant as light, which is used in photosynthesis.
What do chloroplasts contain?
They contain green chlorophyll.
What makes plants green ?
Chloroplasts, they contain green chlorophyll which makes the plant green.
What is the function of the vacuole ?
- It is full of cell sap, a watery solution of sugar and salts
- It helps to keep the cell rigid, so supporting the plant and keeping it upright ( pushing outwards )
What is the function of the cell wall ?
- This surrounds the cell.
- It is made of a tough fibre called cellulose
- It makes the wall rigid and supports the cell
What are Bacteria ?
They are unicellular organisms ( made up of just one cell - prokaryotic )
State three examples of commonly found bacteria ?
- Escherichia coli – Causes food poisoning
- Streptococcus – bacteria causes sore throats
- Streptomyces – bacteria found in soil and used to develop antibiotic streptomycin
Name of primative bacteria-like organisms ?
Archaea
What sub cellular structures do common prokaryotic cells contain ?
- Cell wall ( holds the cell together, protects it )
- Genetic material ( floats freely in the cytoplasm )
- Cell membrane ( A barrier that controls which substances enter/leave )
- Cytoplasm ( where chemical reactions happen )
Describe the genetic material in prokaryotic cells commonly ?
There is one long strand of DNA called the bacterial chromosome. This is normal y circular
List the structures and organelles you would expect to find in some bacteria cells ?
- Cell wall (peptigoglycan)
- Cell membrane
- Flagella
- Single-loop DNA
- Plasmids
- Pili
- Cytoplasm
- Slime capsule
What is the function of the flagella ?
Tail-like structures that allow bacteria cells to move through liquids
What is the function of the Pili ?
- Tiny ‘hair-like’ structures that allow the cell to attach to structures, such a the cells in your digestive tract.
- They are also used to transfer genetic material between bacteria cells.
What is the function of the slime capsule ?
- Protects bacteria from drying out and from poisonous substances.
- Helps bacteria to stick to smooth surfaces
What is the function of the plasmid ?
- A circular piece of DNA found in bacteria cells
- Not needed for day-to-day survival but can give the bacterium advantages such as antibiotic resistance
Name the parts of a light microscope ?
- Body tube
- Fine focussing knob
- Mechanical stage
- Stage
- Objectives
- Course focussing knob
- Revolving nosepiece
- Eyepiece lens
- Mirror
- Arm
- Base
What is the equation for magnification?
Image size = Actual size x Total Magnification
What is resolution ?
- The degree to which it is possible to distinguish between two objects that are very close together, rather than them look merged into one object.
- The higher the resolution, the greater the detail you may see
Name the two types of electron microscopes ?
- Transmission electron microscope (TEM)
- Scanning electron microscope (SEM)
What are TEM used for and how have they advanced science?
- TEM is used to examine an extremely thin slice or section of cells or tissues
- TEM has revealed subcellular structures in cells not visible with a light microscope such as mitochondria and chloroplasts
What are SEM used for and how have they advanced science?
- They produce a 3-D image of a surface by bouncing a beam of electrons off of a specimen.
What are the advantages and disadvantages of light microscope and electron microscopes?
Light microscope :
- Cheep to buy and operate
- Small and portable
- Simple to prepare sample
- Natural colour of sample is seen unless staining is used.
- Specimens living or dead
- Resolution up to 0.2 µm
(2 x 10-7 m)
Electron Microscope :
- Expensive to buy and operate
- Large and difficult to move
- Sample preparation is complex
- Black and white images produced; false colour can be added to images
- Specimens are dead
- Resolution up to 0.1 nm
(1 x 10-10 m)
Why are cells stained ?
So that they are easier to observe, it also highlights specific sub-cellular structures
What are the three common stains ?
- Methylene blue - makes It easier to see the nucleus of an animal cell
- Iodine - This makes it easier to see the plant cell
- Crystal violet - this stains bacterial cell walls
Method for staining cells ?
- Pace the cells on a glass slide
- Add one drop of stain
- Place a coverslip on top
- Tap the coverslip gently with a pencil to remove air bubbles
How do light microscopes work ?
- The microscope passes light through the object on the stage, then through two glass lenses ( the objective lens and the eyepiece )
- The lenses magnify the object so when you look at it you see more detail
