anatomy of the cell

Question 1

eukaryotic cells

Answer 1

features:
an outer membrane
inner cytosol
cytoskeleton
membrane bound organelles within the cytosol

Question 2

plasmalemma (cell membrane)

Answer 2

separates the cytoplasm from the outside environment
fluid
selectively permeable
a phospholipid bilayer with integral and peripheral proteins and cholesterol in it

Question 3

organelles in the cytoplasm

Answer 3

mitochondria- energy production
rough ER- protein synthesis
smooth ER- cholesterol and lipid synthesis/detoxification)
Golgi Apparatus- modification and packaging of secretions
lysosomes- hydrolytic enzymes for intracellular digestion
nucleus- contains genetic code

Question 4

inclusions

Answer 4

they are dispensable and represent components that have been synthesised by the cell itself

Question 5

cytoskeleton proteins

Answer 5

several functions of a cell are maintained by a set of filamentous cytosolic proteins

Question 6

microfilaments

Answer 6

composed of the protein actin

Question 7

intermediate filaments

Answer 7

composed of 6 main proteins, which vary in cell types

the type of protein present can help to identify tumour origins

Question 8

microtubules

Answer 8

composed of tubulin proteins

2 proteins dyneien and kinesin attach to microtubules and move along them

Question 9

kinesin

Answer 9

an ATPase that moves towards the cell periphery

Question 10

dynein

Answer 10

an ATPase that moves towards the call centre

Question 11

nucleus

Answer 11

mRNA and tRNA are transcribed in the nucleus

rRNA is transcribed in the nucleolus, a small dense area within the nucleus

Question 12

nucleus

Answer 12

the nucleus contains Euchromatin, and heterochromatin

Question 13

euchromatin

Answer 13

DNA that is more dispersed and actively undergoing transcription

Question 14

heterochromatin

Answer 14

DNA that is highly condensed and not actively undergoing transcription

Question 15

ribosomes

Answer 15

each ribosome has a small subunit which binds RNA and a large subunit that catalyses the formation of peptide bonds

Question 16

Rough ER

Answer 16

studded with ribosomes

synthesises proteins destined for insertion into membranes or for secretion

Question 17

Smooth ER

Answer 17

continues the processing of proteins produced in the ER

the SER plays a vital role at the site of synthesis of lipids

Question 18

golgi apparatus

Answer 18

transport vesicles arrive at the golgi from the SER/RER

they modify and package macromolecules that were synthesised in the ER

Question 19

intercellular junctions

Answer 19

specialised membrane structures which link individual cells together into a functional unit.
there are three types: occluding, anchoring and communicating

Question 20

occluding junctions

Answer 20

link cells to form a diffusion barrier

prevent diffusion

Question 21

anchoring junctions

Answer 21

provide mechanical strength
link submembrane actin bundles of adjacent cells
transmembrane cadherin molecules bind to each other in the extracellular space and to actin of the cytoskeleton
allow the movement of molecules between cells
desmosomes link submembrane intermediate filaments of adjacent cells. very common in the skin where they provide mechanical stability

Question 22

communicating

Answer 22

allow selective diffusion of molecules between adjacent cells
each junction is a circular patch studded wtih several hundred pores. these pores are produced by connexon proteins