Anatomy of the Cell

Question 1

Name the general components in a cell from most to least

Answer 1

Water
protein
lipid
carbohydrate
inorganic

Question 2

What do all eukaryotic cells contain?

Answer 2

an outer membrane
an inner cytosol/cytoplasm
a cytoskeleton
membrane bound organelles
inclusions

Question 3

What does the

cell membrane do?

Answer 3

Separates inside of cell from outside of cell
Contains integral proteins including receptors, channels, transporters, enzymes and cell attachment proteins.
Can exocytose and endocytose substances across membrane

Question 4

Why is the cell membrane fluid?

Answer 4

Changes shape easily

Membrane proteins can diffuse laterally (some are anchored)

Question 5

Why is the cell membrane selectively permeable?

Answer 5

Water, Oxygen and small HYDROPHOBIC molecules can penetrate the membrane
Charged ions cannot penetrate membrane

Question 6

What does the plasmalemma contain?

Answer 6

integral and peripheral proteins and cholesterol

Question 7

What is the difference between an organelle and an inclusion?

Answer 7

Organelle - necessary for cell function and survival

Inclusion - dispensable and transient

Question 8

What do the Mitochondria do?

Answer 8

Produce energy (ATP)

Question 9

What does the rough endoplasmic reticulum do?

Answer 9

Involved in protein synthesis

Question 10

What does the smooth endoplasmic reticulum do?

Answer 10

Synthesises and detoxifies cholesterol and lipids

Question 11

What does the Golgi Apparatus do?

Answer 11

Modifies and packages proteins

Question 12

Give examples of inclusions

Answer 12

Substances synthesised by cell eg pigments, glycogen stores, lipid droplets,presecretion product
or taken from extracellular envrionment eg endocytotic vesicle

Question 13

Name the three main classes of filaments

Answer 13

Micro filaments
Intermediate filaments
Microtubules

Question 14

Describe the Microfilaments

Answer 14

Made of two strands of actin twisted together
7nm diameter
Easy to assemble and disassemble

Question 15

Describe intermediate filaments

Answer 15

Types divided into classes used to identify origin of tumour in pathology
10 - 15nm

Question 16

Where are neurofilaments found?

Answer 16

nerve cells

Question 17

Where are glial fibrillary acidic proteins found?

Answer 17

Glial cells

Question 18

Where are desmins found?

Answer 18

Muscle cells

Question 19

Where are cytokeratins found?

Answer 19

epithelial cells

Question 20

Where are vimentin found?

Answer 20

mesenchymal cells

Question 21

Where are Filesin found?

Answer 21

lens of eye

Question 22

Where are lamin found?

Answer 22

Nuclei of all cells

Question 23

Describe Microtubules

Answer 23

hollow tube made of alternating alpha and beta tubulin
Can assemble and disassemble
Come from centrosome organising centre (CTOC)

Question 24

What does MAPS stand for?

Answer 24

Microtubule-associated proteins

Question 25

What do microtubules do?

Answer 25

Transport substances from centre of cell to membrane and back Important in cilia, flagella, mitotic spindle, and neurons

Question 26

What are Kinesin and Dynein?

Answer 26

ATPases which associate with organelle/vesicle membranes and transport them along microtubule Kinesin - to cell periphery Dynein - to cell centre

Question 27

What surrounds the nucleus?

Answer 27

Nuclear envelope made of inner and outer membrane | Membranes contain pores to join it up to cytoplasm

Question 28

What is between the inner and outer layer of nuclear membrane?

Answer 28

Perinuclear cistern which is continuous with the cistern of the endoplasmic reticulum

Question 29

What is in the outer nuclear membrane?

Answer 29

Ribosomes | is continuous with rough endoplasmic reticulum

Question 30

Where are mRNA, tRNA, and rRNA transcribed?

Answer 30

mRNA and tRNA in the nucleus | rRNA in the nucleolus

Question 31

What does the nucleus contain?

Answer 31

Euchromatin - DNA currently undergoing transcription | Heterochromatin - DNA not currently undergoing transcription

Question 32

Where are ribosomes formed?

Answer 32

In the nucleolus

Question 33

What is the structure of a ribosome?

Answer 33

Two subunits: - small unit, binds RNA - large unit, catalyses formation of peptide bonds

Question 34

What does reticulum mean?

Answer 34

Net-like structure

Question 35

What is the endoplasmic reticulum?

Answer 35

Network of interconnecting membrane bound compartments

Question 36

What does the rough endoplasmic reticulum do?

Answer 36

Containing embedded ribosomes, it is instrumental in the production of proteins which will be placed in the cell membrane/ secreted

Question 37

What do polysomes produce?

Answer 37

Proteins which will stay in the cytosol

Question 38

Describe the process of protein synthesis including the RER

Answer 38

Ribosome binds to mRNA If ER signal peptide sequence present, new peptide will grow into an ER pore New peptide formed in ER, signal sequence removed Ribosome detaches and protein moves into SER

Question 39

What kind of cells contain large quantities of ER?

Answer 39

Cells which are metabolically active

Question 40

What does smooth endoplasmic reticulum do?

Answer 40

Synthesises lipids | Processes proteins from RER

Question 41

What is the Golgi apparatus?

Answer 41

Several cisternae bound by membranes which modify and package macromolecules produced in ER

Question 42

What can the Golgi apparatus do to modify macromolecules?

Answer 42

Add sugars Cleave proteins Sort into vesicles

Question 43

How are macromolecules transported to Golgi apparatus?

Answer 43

In vesicles

Question 44

describe the structure of a mitochondrion

Answer 44

have an outer and inner membrance inner membrance is folded, creating cristae which increase the total surface area contain their own DNA

Question 45

What does it mean if a cell contains many mitochondria?

Answer 45

Cell is metabolically active

Question 46

What is an intercellular junction? | List the three types

Answer 46

structures which link the membranes of individual cells together Occluding junctions Anchoring junctions Communicating junctions

Question 47

What is an Occluding junction?

Answer 47

an area where proteins from both cell membranes interact and hold the cells together this prevents diffusion between the cells

Question 48

What other names exist for an occluding junction?

Answer 48

Tight junction or zonula occludens

Question 49

What is an Anchoring junction?

Answer 49

When Cadherin molecules which span the membrane bind to each other between the two cells the cadherin is attached to actin in the cytoskeleton via other molecules

Question 50

What other names exist for anchoring junctions?

Answer 50

Adherent junctions or zonula adherens

Question 51

What is a desmosome/macula adherens?

Answer 51

Link between the intermediate filaments of the cytoskeleton of two cells common in epithelial tissue

Question 52

What is a junctional complex?

Answer 52

Several different junctions found very close together

Question 53

What is a communicating junction?

Answer 53

A group of pores between two cells which allows some molecules to diffuse through to the other cell Pores are formed by connexon proteins Also known as gap junctions Allows a wave of excitation to spread (cardiac and smooth muscle)

Question 54

Name the three ways substances can be moved across a cell membrane

Answer 54

Diffusion By the action of transport proteins By vesicular transport

Question 55

What is endocytosis?

Answer 55

When material is brought into a cell by the invagination of the membrane Receptors can control this process

Question 56

What is exocytosis?

Answer 56

The opposite of endocytosis

Question 57

What is phagocytosis?

Answer 57

When a phagocyte takes up material from outside the cell and combines it with lysosomal enzymes to break down the material

Question 58

What is a; phagosome? phagolysosome?

Answer 58

the vesicle containing the material brought in the phagosome with lysosomal enzymes added