Anatomy of the Cell

Question 1

What is the cell membrane? (Plasmalemma)

Answer 1

A biomolecular layer of Amphipathic phospholipids

Question 2

What are the functions of the cell membrane?

Answer 2

Selectively permeable, Allows substances such as water and small hydrophobic molecules to enter the cell while preventing Charged ions.

Question 3

What can be found within the Cell Membrane?

Answer 3

Integral proteins such as receptors, channels, enzymes and cell attachment proteins.

Question 4

Describe the polar and non polar regions of the Phospholipid

Answer 4

Polar Hydrophillic head region of chlorine and phosphate.

Non- Polar Hydrophobic fatty acid chain.

Question 5

What are the small intracellular organs called?

Answer 5

Organelles

Question 6

Name the Organelles found within a Eukaryotic Cell

Answer 6

Mitochondria, Rough ER, Smooth ER, Golgi apparatus, lysosomes and the Nucleus.

Question 7

Whats is the Cytoskeleton?

Answer 7

A set of filamentous cytosolic Proteins. Which determines the shape and fluidity of the cells.

Question 8

What are the Three main classes of filaments and what are the composed of?

Answer 8

Microfilaments - Composed of protein Actin.
Intermediate Filaments - Composed of 6 main proteins which vary
Microtubules - tubulin proteins

Question 9

What are Microfilaments?

Answer 9

Composed of fine strands of the protein Actin. Have a Diameter of 7nm or 0.007µm

Question 10

What are Intermediate Filaments?

Answer 10

Bind intracellular elements together and to the Plasmalemma. There are more than 50 types and vary depending on the proteins which they are composed of. Diameter of 10-15nm.

Question 11

What are Microtubules?

Answer 11

They are composed of Alpha and Beta tubulin subunits. Originate from the centrosome in the centre of the cell. Diameter of around 25nm.

Question 12

What are the Functions of Microtubules aside from structure?

Answer 12

They can help move things around within the cell. Dyen and kinesin attach and can move along while dragging associated organells by their membranes.
Can also help in production of spindle.

Question 13

What is the Nucleus?

Answer 13

Contains genetic code for the cell.

An inner and outer nuclear membrane with a gap - perinuclear cistern.

Question 14

where are mRNA and tRNA transcribed?

Answer 14

In the nucleus - rRNA is transcribed in the nucleolus

Question 15

What are Ribosomes?

Answer 15

Production factory or making proteins.

Question 16

What is the endoplasmic reticulum?

Answer 16

The ER forms a network of interconnecting membrane bound components in the cell.

Question 17

What is the difference between the smooth and Rough ER?

Answer 17

The rough ER is studded with ribosomes and is the site of protein synthesis and initiation of glycoprotein formation.

The Sooth ER continues the processing of proteins from the RER and is the site of lipid synthesis.

Question 18

What is the Golgi apparatus?

Answer 18

Composed of a group of flattened membrane bound cisternae this is where the produced components (macromolecules) from the SER are modified and packaged.

Question 19

Where do the transport vesicles from the SER take the macromolecules?

Answer 19

The Golgi apparatus

Question 20

What are mitochondria?

Answer 20

The powerhouse of the cell they generate ATP. Composed of inner and outer membrane, the inner is invaginated to increase surface area.

Question 21

Where to reactions take place within the Mitochondria?

Answer 21

on the invaginated inner membrane.

Question 22

What are intracellular junctions?

Answer 22

Specialised membrane structures which link individual cells into a functional unit.

Question 23

What are the 3 main types of Intracellular Junctions?

Answer 23

Occluding Junctions, Anchoring Junctions, Communicating Junctions

Question 24

What is an Occluding Junction? (aka zonula occludens)

Answer 24

An occluding junction prevents diffusion by linking cells to produce a diffusion barrier.

Question 25

What is an Anchoring Junction?

Answer 25

Anchoring junctions provide mechanical strength, they link sub-membrane actin bundles of adjacent cells.
Desmosomes link submembrane intermediate filaments of adjacent cells.

Question 26

What are Communicating Junctions?

Answer 26

Allow movement of molecules between cells. Often called gap junctions, Each junction is studded with pores (produced by connexion proteins).
Found in the epithelium, but also in smooth and cardiac muscle.

Question 27

What is a Junctional Complex?

Answer 27

Close association of several types of junctions found in certain epithelial tissues.

Question 28

Name ways in which material can move across the cell.

Answer 28

By Diffusion, Transport proteins (Pumps or channels) or by incorporation into vesicles (endocytosis, phagocytosis)

Question 29

What is Endocytosis?

Answer 29

Material from extracellular space is incorporated into a cell. Cell membrane invaginates, fuses and the newly made endocytotic vesicle buds into the cell.

Question 30

What is Exocytosis?

Answer 30

Material from intracellular space is expelled out of the cell. Vesicle secretes molecules to the extra cellular space.

Question 31

What is Phagocytosis?

Answer 31

Bacterium binds to surface receptors triggering extensions of the cell to engulf it forming a phagosome. This binds with a lysosome which contains digestive enzymes creating a phagolysosome.