Topic 2A- Cell Structure and Division Flashcards
What is the process by which prokaryotic cells divide and give an example?
How often will this happen in ideal conditions?
What is the definition of object?
What is the definition of image?
What are the five main parts of a bacterium cell?
What is the equation for calculating magnification?
What must you make sure when calculating the magnification?
What are the following units written in metres:
Centimetre (cm)
Millimetre (mm)
Micrometre (u|m
Nanometre (nm)
Binary Fission (eg bacteria cells)
They divide once every 20 minutes
This is what you place under the microscope. This is the real size
This is what you see down the microscope or the picture given to you in the exam
Cell wall; cell surface membrane; cytoplasm (containing ribosomes); DNA and Plasmid
Magnification= Image size -:- Actual size
That the measurements for the image and the object are in the same units
- 01 m
- 001 (or 1 x 10-3)
- 000001 (or 1 x 10-6)
- 000000001 (or 1 x 10-9).
What is the description of the following organelles:
Cell-surface (plasma) membrane
Nucleus
Mitochondrion
Chloroplast
Golgi Apparatus
The membrane found on the surface of animal cells and just inside the cell wall of other cells. It’s mainly of lipids and proteins
A large organelle surrounded by a nuclear envelope (double membrane), which contains many pores. The nucleus contains chromosomes (which are made from protein-bound linear DNA) and one or more structure(s) called a nucleolus
They’re usually oval-shaped. They have a double membrane- the inner one is folded to form structures called cristae. Inside is the matrix, which contains enzymes involved in respiration
A small, flattened structure found in plant and algal cells. It’s surrounded by a double membrane, and also has membranes inside called thylakoid membranes. These membranes are stacked up in some parts of the chloroplast to form grana. Grana are linked together by lamellae- thin, flat pieces of thylakoid membrane
A group of fluid-filled membrane-bound flattened sacs. Vesicles are often seen a the edges of the sacs.
What is the function of the following organelles:
Cell-Surface (plasma) Membrane
Nucleus
Mitochondrion
Chloroplast
Golgi Apparatus
Regulates the movement of substances into and out of the cell. It also as receptor molecules on it, which allow it to respond to chemicals like hormones
The nucleus controls the cell’s activities (by controlling the transcription of DNA). DNA contains instructions to make proteins. The pores allow substances (eg RNA) to move between the nucleus and the cytoplasm. The nucleolus makes ribosomes
The site of aerobic respiration, where ATP is produced. They’re found in large numbers in cells that are very active and require a lot of energy
The site where photosynthesis takes place. Some parts of photosynthesis happen in the grana, and other parts happen in the stroma (a thick fluid found in chloroplasts)
It processes and packages new lipids and proteins. It also makes lysosomes.
What is the description of the following organelles:
Golgi Vesicle
Lysosome
Ribosome
Rough Endoplasmic Reticulum (RER)
Smooth Endoplasmic Reticulum (SER)
Cell Wall
Cell Vacuole
A small fluid filled sac in the cytoplasm, surrounded by a membrane and produced by the Golgi apparatus
A round organelle surrounded by a membrane with no clear internal structure. It’s a type of Golgi vesicle
A very small organelle that either floats free in the cytoplasm or is attached to the rough endoplasmic reticulum. It’s made up of proteins and RNA. It’s not surrounded by a membrane
A system of membranes enclosing a fluid-filled space. The surface is covered with ribosomes
Similar to rough endoplasmic reticulum, but with no ribosomes
A rigid structure that surrounds cells in plants, algae and fungi. In plants and algae it’s made mainly of the carbohydrate cellulose. In fungi, it’s made of chitin
A membrane-bound organelle found in the cytoplasm of plant cells. It contains cell sap- a weak solution of sugar and salts. The surrounding membrane is called the tonoplast.
What is the function of the following organelles:
Golgi Vesicle
Lysosome
Ribosome
Rough Endoplasmic Reticulum (RER)
Smooth Endoplasmic Reticulum (SER)
Cell Wall
Cell Vacuole
Stores lipids and proteins made by the Golgi apparatus and transports them out of the cell (via the cell-surface membrane)
Contains digestive enzymes called lysozymes. These are kept separate from the cytoplasm by the surrounding membrane, and can be used to digest invading cells or to break down worn out components of the cell
The site where proteins are made
Folds and processes proteins that have been made at the ribosomes
Synthesises and processes lipids
Supports cells and prevents them from changing shape
Helps to maintain pressure inside the cell and keep the cell rigid. This stops plants wilting. Also involved in the isolation of unwanted chemicals inside the cell.
What is the wavelength of light like and what is a consequence of this?
What is the wavelength of electrons like and what is a consequence of this?
What type of image does a scanning electron microscope produce?
What are the three stages of cell fractionation and describe each one?
What are the organelles separated into in cell fractionation?
What is this order?
What is the mnemonic for remembering this order?
What does isotonic mean in cell fractionation?
Why is the solution buffered?
Why is the solution cold?
Light has a relatively long wavelength and consequently can’t resolve points that are closer than 0.2 um
Electrons have a very short wavelength and therefore a high resolving power
Scanning electron microscope produces a 3D image
Homogenisation- breaking up the cell
Filtration- Getting Rid of the Big Bits
Ultracentrifugation- separating the organelles
Separated in order of mass (from heaviest to lightest)
Nuclei; Chloroplasts; Mitochondria; Lysosomes; ER; Ribosomes
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In this context, means the same water potential in the solution as in the organelles to prevent damage to the organelles
To prevent damage to proteins (prevents denaturation)
The solution is cold to reduce enzyme activity.
Describe how Scanning Electron Microscopes work?
What is an advantage of SEM’s?
What are two disadvantages of SEM’s?
Describe how Transmission Electron Microscopes work?
What is an advantage of TEM’s?
What are the two disadvantages of TEM’s?
Scan a beam of electrons across the specimen. This knocks off electrons from the specimen, which are gathered in a cathode ray tube to form an image. The images you end up with show the surface of the specimen and they can be 3D
They can be used on thick specimens
They give lower resolution images than TEM’s and can only be used on non-living specimens
Use electromagnets to focus a beam of electrons, which is then transmitted through the specimen. Denser parts of the specimen absorb more electrons, which makes them look darker on the image you end up with
They give high resolution images, so you see the internal structure of organelles like chloroplasts
You’ve got to view the specimen in a vacuum, so they’re no good for looking at living organisms. They can also only be used on thin specimens
What are prokaryotic organisms and what does this mean (full description)?
What are eukaryotic organisms and what does this mean (full description)?
What are organelles?
What are the organelles of plant cells?
What is the function of the cellulose cell wall?
What is the function of the vacuole?
What are the three added extra organelles of plant cells?
Describe algal cells and their organelles?
Describe fungal cells and their organelles (full detail)?
Prokaryotic cells (they’re single-celled organisms) and are smaller and simpler (eg bacteria)
Eukaryotic cells which are complex and include all animal and plant cells, as well as all cells in algae and fungi
Organelles are part of cells- each one having a specific function
Same organelles as animal cells but with a few extras
With plasmodesmata (channels for exchanging substances with adjacent cells)
Vacuole (compartment that contains cell sap)
Cellulose cell wall; vacuole and chloroplasts
Algal cells are a lot like plant cells- they have the same organelles, including cell wall and chloroplasts
Fungal cells are a lot like plant cells, but:
- Their cell walls are made of chitin, not cellulose
- They don’t have chloroplasts (because they don’t photosynthesise).
