Lysosomes, Vacuoles and Peroxisomes Flashcards
1
Q
What are lysosomes and their function?
A
- They are membrane-bound sacs and they contain many hydrolytic enzymes.
- The enzymes are used to break down any unwanted material and digest it.
2
Q
What do lysosomes break down?
A
- Excess or worn out organelles.
- Food particles
- Engulfed bacteria ans viruses.
3
Q
What is autophagy?
A
- A process where a cell breaks down and destroys proteins and substances that are located in the cytoplasm which are worn out.
4
Q
What is phagocytosis?
A
- A process were a phagocyte engulfs a harmful microorganism.
- Once the harmful microorganism is engulfed a phagosome (a vesicle) is formed and it binds to the lysosome so it can be digested.
5
Q
What is autolysis?
A
- The destruction of cells/ tissues by their own enzymes.
6
Q
What can lysosomes be known as?
A
- Suicide bags
- Suicide sacs
7
Q
What is the relationship between lysosomes and pH?
A
- As lysosomes have a membrane bound sac, the enzymes that it contains can work at an acidic pH.
- Whereas the cytosol is more alkaline than acidic.
-Cytosol has a pH of 7 and lysosome has a pH of 5.
8
Q
Name five enzymes that can be found in lysosomes.
A
- Acid hydrolase
- Nuclease
- Protease
- Glycosidases
- Lipases
- Phosphatase
- Sulphatases
- Phospholipases
9
Q
What is diaminobenzidine?
A
- It is an organic compound which is used to stain cells.
10
Q
What is Zellweger’s Syndrome?
A
- It is a rare genetic disorder and it is where individuals have an absence of peroxisomes.
- Enzymes have not entered the organelle.
11
Q
What are peroxisomes and their function?
A
- They have a present membrane-bound organelle and they contain a crystal of urate oxidase.
- They participate in the metabolism of fatty acids.
- They contain enzymes that get rid of harmful peroxides.
- They break down hydrogen peroxide.
12
Q
What is beta-oxidation?
A
- It is a process that occur in the mitochondria and it is where long fatty acids are broken down into acetyl CoA and then producing ATP.
- It is a source of metabolic energy.
13
Q
What do peroxisome enzymes oxidise?
A
- Fatty acids
- Alcohol
- Toxic compounds
- D-amino acids
14
Q
What enzyme can be found in a peroxisome?
A
- Catalase and it breaks down hydrogen peroxide.
15
Q
What is catalase?
A
- It is an enzyme that breaks down hydrogen peroxide into water and oxygen molecules.
16
Q
Types of enzymes found in lysosomes and peroxisomes.
A
- The types of enzymes found in lysosomes are not specific and this is due to the material they are digesting.
- The types of enzymes that are found in peroxisomes are specific.
17
Q
What are some other function peroxisomes have?
A
- They regulate the O2 tension in the cell.
- Has a role in bile acids and bile protein production.
18
Q
What is the name of peroxisomes that germinating seeds contain?
A
- Glyoxysome
19
Q
What does glyoxysomes do?
A
They carry out the glyoxylate cycle
20
Q
What enzymes are present in glyoxysomes?
A
- Urate oxidase and glycol ate oxidase.
21
Q
What are plasmalogens and how are they produced?
A
- They are lipids and they are produced by peroxisomes.
- They are lipids that contribute greatly in the myelin sheath that insulates nerve cells axons.
22
Q
What happens when there is a deficiency of plasmalogens?
A
- Abnormalities occur in the myelination of nerve cells.
- Can lead to neurological diseases.
23
Q
What is a plasmalogen made up of?
A
- A fatty acid
- A fatty alcohol
- A polar head group attached to glycerol backbone by an ester linkage.
24
Q
Describe a vacuole.
A
- They are membrane bound organelles.
- The membrane is called tonoplast.
- Plant cells contain large vacuoles and some animals do contain them but not all animal cells have them.
25
What are functions of a vacuole?
- They remove unwanted waste and debris.
- Contain waste products.
- Have an acidic pH.
- Play a big role in autophagy.
- Store food and other material needed by cells.
- In plants they contain the cell sap.
26
What are the two types of vacuoles?
- There are food vacuoles and they are used by macrophages as a stage of phagocytosis.
- Contractile vacuoles are used to pump excess water out of the cell and this is to reduce osmotic pressure and prevent bursting of the cell.
27
What is cytolysis/ osmotic lysis?
When a cell burst as the osmotic pressure is too high.
28
Describe vacuoles in plants.
- Contain a lot of cell sap.
- They push the cell contents against the membrane to keep chloroplast closer to the light so they can absorb light energy which can be used for photosynthesis.
- Store pigments in fruits and flowers.
29
What does the plant cell sap contain?
It contains:
- Water
- Enzymes
- Inorganic ions
- Toxic byproducts
30
What is tugor pressure?
- It is a force that pushes the plasma membrane against the cell wall; tugor makes a plant rigid.
31
What is plasmolysis?
When there is a decrease in water in a cell and the cell shrinks.
- The cell membrane moves away from the cell wall.
32
What is phagocytosis?
- When bacteria is engulfed by a vacuole.
33
What is pinocytosis?
- The ingestion of a substance that is in a liquid by small vesicles.
