TOB Session 3 Flashcards Preview

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Flashcards in TOB Session 3 Deck (28)
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1
Q

Define “limit of resolution”

A

The minimum distance that two objects can be distinguished at.

2
Q

Why are electron microscopes more capable of finer resolution than light microscopes?

A

Because limit of resolution is proportional to wavelength and the wavelength of light is aproximately 100x that of electrons.

3
Q

What is an endosome?

A

A small membrane bound compartment involved in endocytosis

4
Q

What is a peroxisome?

A

They are organelles involved in the catabolism of long chain fatty acids. They look like dark coloured vesicles. They are the major site of H2O2 production and oxygen utilisation. They are bound by a single membrane and are self replicating.

5
Q

What is cytosol?

A

The cytoplasmic matrix.

6
Q

What is a lysosome?

A

Cellular organelles that hydrolase enzymes to breakdown debris. They are light coloured vesicles. They contain acid hydrolases at pH5 and their membranes are highly glycosylated for protection.

7
Q

What is the Golgi Apparatus?

A

Stacks of disc like cisternae where glycosylation of proteins and lipids takes place. They have polarity so proteins migrate from the convex (cis) to concave (trans) face of the stack. The Golgi apparatus sorts, modifies, concentrates and packages the proteins from the Rough Endoplasmic Reticulum.

8
Q

What does a mitochondria look like and what does it do?

A

Double membraned organelle with inner membrane folded into cristae. Uses glucose and fatty acids to generate ATP. The inner matrix contains enzymes, DNA, RNA, ribosomes and calcium granules. Mitochondria are inherited by maternal lineage.

9
Q

What does the rough endoplasmic reticulum look like and do?

A

The rough endoplasmic reticulum is an interconnected network of tubules studded with ribosomes. It is involved in the synthesis of proteins. The membrane is attached to the nuclear envelope and it has vesicles that shuttle to and from the Golgi apparatus.

10
Q

What are ribosomes for?

A

Ribosomes are used for protein synthesis. They are where translation takes place.

11
Q

What does the nucleus of a cell look like? What does it do?

A

It is the largest organelle and on a micrograph it will look like a large dark circle. It stores the cell’s DNA and co-ordinates the cell’s activity. Most nuclear material consists of chromatin.

12
Q

Where would you find the plasma membrane?

A

The plasma membrane is found around the outside of the cell.

13
Q

What does amphipathic mean?

A

That the compound has both a hydrophilic end a hydrophobic end.

14
Q

What is the main function of the phospholipid bilayer membrane?

A

To form a relatively impermeable barrier to most water soluble molecules. The protein molecules in the bilayer mediate most of the other membrane functions.

15
Q

What is the glycocalyx?

A

The glycocalyx is the cell ‘coat’. It is made up of oligosaccharide and polysaccharide chains on the outside of the plasma membrane.

16
Q

What is the plasmalemma?

A

The plasma membrane

17
Q

What are the functions of the plasmalemma?

A

Selective permeability
Endo/exocytosis
Transport of materials along cell surface
Intercellular adhesion

18
Q

What is the nuclear envelope?

A

A double layered membrane separating the contents of the nucleus from the cytoplasm.

19
Q

What is the purpose of the nuclear pores?

A

To allow specific molecules in and out of the nucleus and cytoplasm.

20
Q

What is the nucleolus and where would you find it?

A

The nucleolus is inside the nucleus and it synthesises ribosomes.

21
Q

Where might you find smooth endoplasmic reticulum?

A

In the liver, mammary gland, ovaries, testes and adrenal glands. It has no ribosomes.

22
Q

What is a residual body?

A

A lysosome that has digested its contents but still contains indigestible remnants.

23
Q

What are the three main types of cytoskeleton?

A

Microfilaments, Intermediate filaments and microtubules

24
Q

What is the purpose of the cytoskeleton?

A

It is responsible for maintaining/changing cell shape. It provides structural support and a means of movement for organelles, plasma membrane etc.

25
Q

What are the properties of microfilaments?

A

They are 5nm in diameter.
They consist of 2 actin strings twisted together.
They are contractile and can assemble and dissociate.

26
Q

What are the properties of intermediate filaments?

A

They are 10-12nm in diameter and are common in nerve and neurological cells.
They are not dynamic
They are anchored to plasma membrane at strong intercellular junctions

27
Q

What are the properties of microtubules?

A

They are 25nm in diameter.
13 alpha and beta subunits polymerise, originating from the centrosome.
They are found at sites where structures in cells are moved e.g. flagella, mitotic spindle, nerve fibres, cilia.

28
Q

In what arrangment are the microtubules in a cilium or flagellum arranged?

A

9+2 arrangement