Question 1

3 Features of eukaryotic cells

Accepted Answer

histones (proteins associated with dan)
membrane- bound organelles in the cytoplasm
distinct nucleus containing DNA which is surrounded by a nuclear envelope

Question 2

Function of Nuclear Membrane (nuclear envelope)

Accepted Answer

containment of genetic material

Question 3

Function of Nuclear pores

Accepted Answer

communication b/w nucleus & cytoplasm

Question 4

Function of Heterochromatin

Accepted Answer

Portion of genome not being transcribed

Question 5

Function of Euchromatin

Accepted Answer

Active transcription of genetic material

Question 6

Function of Chromosomes

Accepted Answer

Condensed chromatin during cell division

Question 7

Function of Nucleolus

Accepted Answer

produces rRNA

Question 8

4 components of a nucleus

Accepted Answer

nuclear envelope, chromatin, nucleolus, nuclear matrix

Question 9

3 Functions of The Plasma Membrane

Accepted Answer

- highly selective filter & device for active transport
- generates differences in ion concentration b/w interior +exterior of cell
- a sensor of external signals, allowing the cell to change in response to its environment

Question 10

Common general structure of membranes of eukaryotic cells

Accepted Answer

lipids, proteins & carbs

Question 11

3 Features of lipids (plasma membrane)

Accepted Answer

-basic framework of all membranes is a double layer of lipid molecules
- serves as a relatively impermeable barrier of most water-soluble molecules
- constitutes 50% of mass of most animal membranes

Question 12

List 3 major lipids

Accepted Answer

phospholipids
cholesterol
glycolipids

Question 13

Features of Phospholipids (3)

Accepted Answer

most common of membrane lipids, contains hydrophilic head (soluble in water) and 2 hydrophobic tails, In water tends to spontaneously aggregate with tails pointed inwards & heads exposed to the water. thus forms bilayers.

Question 14

Features of Cholesterol (3)

Accepted Answer

up to 1 cholesterol molecule for every phospholipid molecule. 1 hydrophobic tail & hydrophilic tail. Permeability decreases of lipid bilayers to small water soluble molecules.

Question 15

Function of Glycolipids (5)

Accepted Answer

Only found in outer half of bilayer, sugar groups exposed at the cell surface, constitute about 5% of lipid in outer monolayer, functions largely unknown, most have a hydrophilic head + 2 hydrophobic fatty acid chains.

Question 16

Function of proteins in plasma membrane (4)

Accepted Answer

Transport specific molecules across membrane
Enzymes catalyse reactions at the membrane
Provide links b/w membrane & cytoskeleton, the extra-cellular matrix & adjacent cells. 
Receptors for receiving & transducing chemical signals

Question 17

Features of carbs in plasma membrane (4)

Accepted Answer

Play important roles in cell-cell & cell matrix recognition process
All eukaryotic cell have carbs on their surface whether bound to proteins/lipids
When exposed at the cell surface, carry sugar residues
sugar groups are located only on outside of cell

Question 18

First Feature of biological membranes

Accepted Answer

Membranes are asymmetrical as carbs only attach to outer layer & lipid + protein compositions of the outer + inner layers differ in ways that reflect the diff functions of these surfaces.

Question 19

2nd feature of biological membranes

Accepted Answer

The membrane is a dynamic, fluid structure: most of the lipids & proteins can move freely within their own mono-layer. There is v.little movement across mono-layers.

Question 20

7 Features of Cell Organelles

Accepted Answer

mitochondria, ribosomes, RER, SER, Golgi Apparatus, Lysosomes, secretory vesicles

Question 21

What is Mitochondria and main fuction

Accepted Answer

An organelle found in large numbers in most cells (all eukaryotic cells), in which the biochemical processes of respiration and energy production occur.

Question 22

Features of Mitochondria

Accepted Answer

It has a double membrane, the inner part being folded inwards to form layers (cristae).Skeletal + cardiac muscles need a lot of mitochondria.

Question 23

3 Functions of Mitochondria

Accepted Answer

Transfer energy into metabolites that is accessible to the cell. Energy may be needed for osmotic, mechanical, electrical or chemical work. Tend to accumulate where metabolic activity is more intense.

Question 24

Features/Function of Ribosomes (5)

Accepted Answer

Small particles (20x30nm). Composed of rRNA & almost 80 proteins. Individual ribosomes held together by a  strand of mRNA. Found in all cells. Role in translation: message on mRNA translated into the amino acid sequence of proteins

Question 25

RER function  (rough endoplasmic reticulum)

Accepted Answer

Principle role is to segregate proteins destine for export or intracellular communication from other components of cytoplasm. Prominent in cells specialised for protein secretion. (e.g fibroblasts / pancreatic acinar cells)

Question 26

SER (smooth endoplasmic reticulum) (5)

Accepted Answer

3D network of membraneous tubules. No associate ribosomes. involved in breakdown of glycogen. involved in detoxification of hormones + drugs. calcium release.

Question 27

The Golgi Apparatus (2)

Accepted Answer

-concentrates, chemically modifies, sorts & packages secretory products synthesised in RER (like a post office). Consist of several flattened membranous sacs/cisternae stacked in parallel array

Question 28

Lysosomes (3)

Accepted Answer

They are membrane bound vesicles that contain a large range of hydrolytic enzymes present in all cells. They EAT & DESTROY! Main function is intracytoplasmic digestion.

Question 29

Secretory Vesicles (3)

Accepted Answer

- Found in cells that store a product until its release. Regulative secretion does not need signals while constitutive secretion does.

Question 30

Major components of cytoskeleton

Accepted Answer

Microtubules, Microfilaments, Intermediate filaments, actin

Question 31

Major functions of cytoskeleton (5)

Accepted Answer

Important roles in: movement of organelles within cell, maintaining shape of cells, cell movement (including contraction), movement of parts of cells (cilia), certain specialised cell functions

Question 32

Function of Microtubules

Accepted Answer

involves rapid polyerisation/depolyerisation during cell division

Question 33

Function of Cilium/Flagellum

Accepted Answer

moves the mucus upwards & out. Several mutations have been describe in the proteins of the cilia.

Question 34

Function of Centriole

Accepted Answer

Mytosis: 3 types of cells. Cells that have a high turnover (skin, blood cells, gut cells), permanent cells (don't undergo mitosis) and cells that turnover only when needed.

Question 35

Microfilaments

Accepted Answer

Actin & myosine filaments. Both proteins present in most cells, not just muscle cells

Question 36

Actin (4)

Accepted Answer

very abundant in most cells. globular molecules arranged in double helix. Important for cell mobility. Usual in high concentrations at cell periphery,

Question 37

Myosin (3)

Accepted Answer

low abundance in most cells, high abundance in muscle, in non-musce cells cannot be seen by conventional microscope

Question 38

Microvilli

Accepted Answer

microscopic cellular membrane protrusions that increase the surface area of cells,[1] and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction.

Question 39

RER features (3)

Accepted Answer

consists of tubules & stacks of flattened membranous cistern. continuous with outer nuclear membrane. outer surface strutted with ribosomes.

Cell biology

Week 1

Question	Answer
3 Features of eukaryotic cells	histones (proteins associated with dan) membrane- bound organelles in the cytoplasm distinct nucleus containing DNA which is surrounded by a nuclear envelope
Function of Nuclear Membrane (nuclear envelope)	containment of genetic material
Function of Nuclear pores	communication b/w nucleus & cytoplasm
Function of Heterochromatin	Portion of genome not being transcribed
Function of Euchromatin	Active transcription of genetic material
Function of Chromosomes	Condensed chromatin during cell division
Function of Nucleolus	produces rRNA
4 components of a nucleus	nuclear envelope, chromatin, nucleolus, nuclear matrix
3 Functions of The Plasma Membrane	- highly selective filter & device for active transport - generates differences in ion concentration b/w interior +exterior of cell - a sensor of external signals, allowing the cell to change in response to its environment
Common general structure of membranes of eukaryotic cells	lipids, proteins & carbs
3 Features of lipids (plasma membrane)	-basic framework of all membranes is a double layer of lipid molecules - serves as a relatively impermeable barrier of most water-soluble molecules - constitutes 50% of mass of most animal membranes
List 3 major lipids	phospholipids cholesterol glycolipids
Features of Phospholipids (3)	most common of membrane lipids, contains hydrophilic head (soluble in water) and 2 hydrophobic tails, In water tends to spontaneously aggregate with tails pointed inwards & heads exposed to the water. thus forms bilayers.
Features of Cholesterol (3)	up to 1 cholesterol molecule for every phospholipid molecule. 1 hydrophobic tail & hydrophilic tail. Permeability decreases of lipid bilayers to small water soluble molecules.
Function of Glycolipids (5)	Only found in outer half of bilayer, sugar groups exposed at the cell surface, constitute about 5% of lipid in outer monolayer, functions largely unknown, most have a hydrophilic head + 2 hydrophobic fatty acid chains.
Function of proteins in plasma membrane (4)	Transport specific molecules across membrane Enzymes catalyse reactions at the membrane Provide links b/w membrane & cytoskeleton, the extra-cellular matrix & adjacent cells. Receptors for receiving & transducing chemical signals
Features of carbs in plasma membrane (4)	Play important roles in cell-cell & cell matrix recognition process All eukaryotic cell have carbs on their surface whether bound to proteins/lipids When exposed at the cell surface, carry sugar residues sugar groups are located only on outside of cell
First Feature of biological membranes	Membranes are asymmetrical as carbs only attach to outer layer & lipid + protein compositions of the outer + inner layers differ in ways that reflect the diff functions of these surfaces.
2nd feature of biological membranes	The membrane is a dynamic, fluid structure: most of the lipids & proteins can move freely within their own mono-layer. There is v.little movement across mono-layers.
7 Features of Cell Organelles	mitochondria, ribosomes, RER, SER, Golgi Apparatus, Lysosomes, secretory vesicles
What is Mitochondria and main fuction	An organelle found in large numbers in most cells (all eukaryotic cells), in which the biochemical processes of respiration and energy production occur.
Features of Mitochondria	It has a double membrane, the inner part being folded inwards to form layers (cristae).Skeletal + cardiac muscles need a lot of mitochondria.
3 Functions of Mitochondria	Transfer energy into metabolites that is accessible to the cell. Energy may be needed for osmotic, mechanical, electrical or chemical work. Tend to accumulate where metabolic activity is more intense.
Features/Function of Ribosomes (5)	Small particles (20x30nm). Composed of rRNA & almost 80 proteins. Individual ribosomes held together by a strand of mRNA. Found in all cells. Role in translation: message on mRNA translated into the amino acid sequence of proteins
RER function (rough endoplasmic reticulum)	Principle role is to segregate proteins destine for export or intracellular communication from other components of cytoplasm. Prominent in cells specialised for protein secretion. (e.g fibroblasts / pancreatic acinar cells)
SER (smooth endoplasmic reticulum) (5)	3D network of membraneous tubules. No associate ribosomes. involved in breakdown of glycogen. involved in detoxification of hormones + drugs. calcium release.
The Golgi Apparatus (2)	-concentrates, chemically modifies, sorts & packages secretory products synthesised in RER (like a post office). Consist of several flattened membranous sacs/cisternae stacked in parallel array
Lysosomes (3)	They are membrane bound vesicles that contain a large range of hydrolytic enzymes present in all cells. They EAT & DESTROY! Main function is intracytoplasmic digestion.
Secretory Vesicles (3)	- Found in cells that store a product until its release. Regulative secretion does not need signals while constitutive secretion does.
Major components of cytoskeleton	Microtubules, Microfilaments, Intermediate filaments, actin
Major functions of cytoskeleton (5)	Important roles in: movement of organelles within cell, maintaining shape of cells, cell movement (including contraction), movement of parts of cells (cilia), certain specialised cell functions
Function of Microtubules	involves rapid polyerisation/depolyerisation during cell division
Function of Cilium/Flagellum	moves the mucus upwards & out. Several mutations have been describe in the proteins of the cilia.
Function of Centriole	Mytosis: 3 types of cells. Cells that have a high turnover (skin, blood cells, gut cells), permanent cells (don't undergo mitosis) and cells that turnover only when needed.
Microfilaments	Actin & myosine filaments. Both proteins present in most cells, not just muscle cells
Actin (4)	very abundant in most cells. globular molecules arranged in double helix. Important for cell mobility. Usual in high concentrations at cell periphery,
Myosin (3)	low abundance in most cells, high abundance in muscle, in non-musce cells cannot be seen by conventional microscope
Microvilli	microscopic cellular membrane protrusions that increase the surface area of cells,[1] and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction.
RER features (3)	consists of tubules & stacks of flattened membranous cistern. continuous with outer nuclear membrane. outer surface strutted with ribosomes.

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