Cell Structure Flashcards
What are eukaryotic organisms made up of
Eukaryotic organisms are made up of eukaryotic cells
What is a prokaryotic organism?
A single celled organism that is a prokaryotic cell.
Examples of eukaryotic organisms
Plants and animals
Examples of prokaryotic organisms
Bacteria
What is a cell organelle
A cell organelle is part of a cell that carries out a specific function
Name all organelles in a animal cell
Plasma surface membrane R.e.r Nucleolus Nucleus S.e.r Lysosome Ribosome Nuclear envelope Golgi apparatus Cytoplasm Mitochondrion
What extra three organelles do plant cells have
A cell wall with plasmodesmata
A cell vacuole
Chloroplasts
Describe the plasma membrane
In animals found on the cell surface and in plants inside the plant cell wall. Made of mainly lipids and proteins
What is the function of the plasma membrane
Controls what enters and leaves the cell also has receptors on the surface which respond to chemicals such as hormones
Describe the structure of the cell wall
It has a rigid structure that surround the plant cell and is made of cellulose
What is the function of the cell wall
It supports the plant cell
Describe the nucleus
Surrounded by a nuclear envelope that contains many pores. It contains chromatin and often a structure called the nucleolus
What is chromatin made of
Proteins and DNA
What does the DNA inside the nucleus do
Controls the cell activities
What do nuclear pores allow
The allow substances to pass from the cytoplasm and nucleus
What is the function of the nucleolus
It makes ribosomes
Describe the structure of a Lysosome
Round organelles surrounded by a membrane with no clear internal structure
What is the function of the Lysosome
It contains powerful digestive enzymes that digest invading cells or worn out cell components
Describe the structure of a ribosome
It is a small organelle made up of a small subunit and a large subunit. Floats free in the cytoplasm or attached to the R.e.r
Function of a ribosome
It is the site at which proteins are made
Describe the R.E.R
A system of membrane enclosing a fluid filled space with attached ribosomes
What functions do the RER carry out
Folds and processes proteins that have been made at the ribosomes
Describe the structure of the SER
Similar to RER without ribosomes
What is the function of the SER
Synthesises and processes lipids
Describe the structure of the vesicle
Small fluid filled sac surround by a membrane found in the cytoplasm
What is the function of the vesicle
Transport substances in and out the cell AND to and form organelles
Describe the structure of the Golgi body
A group of flattened fluid filled sacs. Vesicles can be found at the edge
What is the function of the Golgi body
Processes and packages proteins and lipids. Also makes lysosomes
Describe the structure of a centriole
Small, hollow rings containing a ring microtubules
What is the function if a centriole
Involved with the separation of chromosomes during cell division
Describe the structure of cilia
Hair like structure found on the membrane of some animal cells. In a cross section of cilia, a ring of nine pairs of microtubules on the inside with, a pair in the middle.
What is the function of cilia
Microtubules allow the cilia to move, as the cilia move it allows substances to move along the cell surface.
Describe the structure of the flagellum
Similar to cilia but longer, sticking out from the cell surface and surrounded by a plasma membrane
What is the function of flagellum
As the microtubules contract, the flagellum moves propelling the cell forward. E.g. Used in sperm.
Describe the structure of a mitochondrion
Oval shaped. it has a double membrane. The inner membrane folds to form a cristae. Inside the matrix, which contains enzymes involved in respiration
Is the function of a mitochondrion
The site of a aerobic respiration, where ATP is produced.
What is the structure of a chloroplast.
Surrounded by a double membrane. Also has membranes inside which stack up to form grana and are joined together by lamellae. There is also a fluid called stroma
What is the function of a chloroplast
Site of photosynthesis. Some occurs in grana and others in the stroma
Describe protein production when it is produced at the RER
Produced at ribosome attached to RER
Folded and processes at RER (eg sugar chains added)
Transported in vesicle to Golgi body
At Golgi body further processing
Transported in a vesicles in or out the cell
Where do proteins in the cytoplasm stay?
They STAY IN THE cytoplasm!!!!
What is the cytoskeleton?
The network of protein threads running through the cytoplasm
What are the protein thread in the cytoskeleton arranged
They are arranged as microfilaments and microtubules.
Four main function of the cytoskeleton
Microtubules and microfilaments support all organelles, keeping them in place.
Maintain and strengthen cell shape.
Transport the organelles and the materials within the cell
Proteins in the cytoskeleton can cause the cell to move.
Compare cell size between eukaryotic and prokaryotic cells
Prokaryotic small less that two micro metres, eukaryotic cells larger two to two hundred micro metres.
Compare dna between eukaryotic and prokaryotic cells
DNA is circular in prokaryotic cells, it is free in cytoplasm and DNA is linear and found within the nucleus in eukaryotic cells
Compare cell walls between eukaryotic and prokaryotic cells
Prokaryotic - made of peptidoglycan Eukaryotic Animal - no Plant - cellulose Fungi - chitin
Compare cell organelles between eukaryotic and prokaryotic cells
Prokaryotic - no membrane bound
Eukaryotic - many membrane bound
Compare ribosomes between eukaryotic and prokaryotic cells
Smaller in prokaryotic cells and larger in eukaryotic
What is the formula for magnification
Magnification = length of image/length of specimen
List the common units for magnification
Millimetres 1mm
Micrometres 0.001 mm
Nanometres 0.000001mm
In magnification how do you go from a smaller to a bigger unit
Divide by 1000
State the two types of micro scope and their resolution
Light and it has a very low resolution
Electron and they have very high resolutions
How does a transmission electron microscope work?
Electromagnets to focus a beam of electrons, which is then transmitted through a specimen, denser parts absorb more electrons making them appear darker
Advantages of TEM
High resolution images
Disadvantages of TEM
Must be thinly sliced
How does a SEM work
Scan a beam of electrons across the specimen this knocks of electrons, they gather in the cathode ray tube to form an image
Advantage of SEM
The images can be 3D
Disadvantages of SEM
Lower resolution images when compared to TEM
Compare resolution across the microscopes
Light is 0.2 micrometers
TEM is 0.0001 micrometers
SEM is 0.005 micrometers
Compare the magnification across the microscopes
Light is x1500
TEM is x 1,000,000 more than
SEM is x1,000,000 less than
Describe staining samples for both types of microscopes
In light microscopes using a dye type stain such as methylene blue, creates contrast needed
In electron microscopes, the objects are dipped in metals such as leads for a contrast to occur
