Cell Structure And Membranes 1.3 Flashcards
What is the function of the nucleus?
It contains the nucleolus and often chromatin. Chromatin is made from DNA and proteins. DNA controls the cells activities. The pores allow substances (RNA) to move between the nucleus and the cytoplasm. The nucleolus makes ribosomes.
What is the function of the plasma membrane?
It regulates the movement of substances into and out of the cell. It also has receptor molecules on it, which allow it to respond to chemicals like hormones.
What do lysosomes contain?
Digestive enzymes
Where are proteins made?
Ribosomes
What is the function of the SER? And the RER?
The SER synthesises and processes lipids, the RER folds and processes proteins.
What is the function of the Golgi apparatus?
It processes and packages new lipids and proteins. It also makes lysosomes.
Describe the structure of a mitochondrion.
They’re usually oval shaped. They have a double membrane. The inner membrane is folded to form structures called cristae, inside is the matrix, which contains enzymes involved in respiration.
What is the equation for magnification?
Length of image\length of specimen
Name the two main types of microscopes.
Light and electron.
Name the two main types of electron microscopes.
Transmission electron microscopes (TEMs) and Scanning electron microscopes (SEMs)
Name one advantage and disadvantage of TEMs.
High resolution images but can only be used on thin specemins.
What is homogenisation?
It is where you vibrate or grind a cell so that it breaks the plasma cell and releases the organelles into the cytoplasm.
Outline the main steps of cell fractionation.
Step 1: homogenisation
Step 2: filtration
Step 3: ultracentrifugation, this is where the organelles are spun in a centrifuge. The heavier organelles sink to the bottom and form a pellet. The lighter organelles form the supernatant and are drained off.
This is done over and over again at higher and higher speeds.
What is a triglyceride made out of?
4 molecules, 3 fatty acids and one glycerol molecule.
What do all fatty acids have in common?
A C=O group, an OH group and a variable group (R)
What is the difference between a phospholipid and a triglyceride?
Phospholipids have a phosphate group instead of a third fatty acid.
How do you test for lipids?
Using the emulsion test for lipids. Shake the test substance with ethanol for a minute. Then pour the solution in water. If a lipid is present a white milky emulsion will form.
What factors affect the rate of diffusion?
Concentration gradient, the higher the faster.
Thickness of exchange surface
The surface area
What does isotonic mean?
When two solutions have the same water potential .
Outline one similarity and difference between active transport and facilitated diffusion?
Difference: facilitated diffusion moves down the concentration gradient, whereas active transport moves against.
Similarity: they both use carrier proteins. (Carrier proteins change shape)
How are co-transporters used in facilitated diffusion?
Co-transporters are a type of carrier protein.
They bind two molecules at the same time.
The concentration gradient of one of the molecules is used move the other against its own.
How does glucose enter the blood?
- Sodium ions are actively transported out of the small intestine epithelial cells, into the blood by the sodium potassium pump.
- This decreases the the concentration of sodium in the epithelial cells so sodium ions diffuse from the small intestine lumen into the cell via the sodium-glucose transporter proteins.
- The concentration of glucose in the cell increases so it diffuses through a channel protein into the blood.
What are eukaryotic cells?
All Animal and plant cells
Name 2 structures in a cholera bacteria which are not in a eukaryotic cell.
Flagellum
Plasmid
Slime capsule
What does a ORS contain?
They contain large amounts of salts (sodium and chloride ions) and sugars (such as glucose and sucrose) also carbohydrates.
Name one advantage of an ORS
Quick, easy to use.
