2.1.1

What is the cell theory?

Cells are smallest form of life

Cells come from pre-existing cells

all living things are made of cells

2.1.2

What evidence is there for the cell theory?

The use of microscopes, especially electron microscopes

also the fact that sterilised substances don't spontaneously support growth.

2.1.4

What is the approximate size of molecules and cell membrane thickness?

Molecules: 1 nanometer

Cell membrane thickness: 10 nanometers

2.1.4

What are the approximate sizes of cells, organelles, bactera and viruses?

Cells: 10-100 micrometers

Organelles: 1-10 micrometers

Bacteria: 1 micrometer

Virus: 100 nanometers

2.1.6

What is the importance of surface area to volume ration in cell size?

In order for cells to get materials, nutrients etc. it uses diffusion.  If the surface area to volume ratio is too large then the distance for diffusion is too far and it becomes inefficient.

2.1.8

How do cells in multicellular organisms carry out specialised functions?

Cells can be specialised.  In order to do this they only express the genes necessary for their particular function.

2.1.9

What are stem cells?

Cells that retain the capacity to divide and have the ability to differentiate along different pathways.

2.1.10

What is one therapeutic use of stem cells?

Bone marrow tranplants.

2.2.1

Draw and Label E.Coli as an example of a prokaryotic cell

2.2.2

What is the purpose of the cell wall and the cell membrane?

The cell wall forms a protective layer that prevents damage from the outside and busting if the internal pressure is high

the cell membrane controls the entry and exit of substances

2.2.2

What is the purpose of The Pili and Flagella in prokaryotes?

The Flagella are large structures used for movement

Pili are smaller structures that can be ratcheted out and used to connect cells together.

2.2.2

What is the purpose of Ribosomes and the Nucleoid in prokaryotes?

Ribosomes synthesise proteins.

The nucleoid is the region of the cytoplasm that contains DNA

2.2.4

How to prokaryotic cells divide?

Binary Fission

2.3.1

Draw and Label a liver cell as an example of a eukaryotic cell.

2.3.2

What is the purpose of the mitochondria and the nucleus in eukaryotes?

The mitochondria are the site of aerobic respiration.

The nucleus controls the cells activities

2.3.2

What is the purpose of the golgi apparatus and the RER?

The Golgi apparatus modifies and packages proteins for transport.

RER transports proteins

2.3.2

What is the purpose of lysosomes and free ribosomes in eukaryotic cells?

Lysososmes contain hydrolytic enzymes that break down unwanted substances in the cell.

Free ribosomes are the site of protein synthesis.

2.3.4

What is the difference between prokaryotic and eukaryotic cells?

Prokaryotes/Eukaryotes

Naked DNA/Chromosomes in a nucleus

no mitochondria/mitochondria

smaller ribosomes/larger ribosomes

few internal membranes/many internal membranes

2.3.5

What are differences between plant and animal cells?

Plant/Animal

Cell wall/No cell wall

chloroplasts/mitochondria

starch/glycogen

Fixed shape/changeable shape

vacuole/no vacuole

2.3.6

What are 2 roles of extra cellular components?

Cell wall

Hyaline cartilage

2.4.1

Draw and label a diagram of a cell membrane

2.4.2

How do phospholipids help to maintain the structure of the cell membrane?

Heads are hydrophilic

Tails are hydrophobic

 This means that in water the phospholipids form double layers.  The attractions between the tails and the heads and water makes the membrane very stable

2.4.3

What are functions of membrane proteins?

hormone binding sites

cell adhesion

enzyme binding site

cell to cell communication

channels for passive transport

pumps for active transport

2.4.4

What is diffusion and osmosis?

Diffusion is the moving of particles from an area of high concentration to an area of low concentration.

Osmosis is the moving of water from an area of low solute to an area of high solute through a partially permeable membrane

2.4.5

How does passive transport across membranes work?

Passive transport can either be facilitated or simple diffusion.

In simple diffusion the molecules simply move through the phospholipids of the membrane

In facilitated diffusion the substance moves through a protein channel

2.4.6

What is the role of ATP and protein pumps in active transport?

Active transport moves substances against a concentration gradient.  Energy is required for this, so ATP provides the energy

2.4.7

How do vesicles transport materials within a cell?

Proteins are made in the ribosomes in the RER.  These proteins then move into the RER to be transported.  Vesicles bud off the RER and move to the golgi apparatus.  The golgi apparatus modifies the protein and then repackages it.  The vesicles carry the protein to the cell membrane where they fuse with the membrane and expel their contents.

2.4.8

What is the advantage of the cell membrane during endocytosis and exocytosis?

The membrane is fluid.  This means that it can break, change it's shape and reform.  This allow it to form vesicles quite easily.

2.5.1

What are the stages in the cell cycle?

Mitosis

Interphase - made of G1, S, and G2.

2.5.2

What are tumours the result of?

Uncontrolled cell division.  Can occur in any organ or tissue.

2.5.3

What is Interphase?

An active time in the life of a cell in which many metabolic reactions occur.  this includes, protein synthesis, DNA replication, and an increase in the amount of mitochondria/chloroplasts.

2.5.4

What events occur during mitosis?

Prophase - Chromosomes become shorter and fatter and spindle microtubules start to form

Metaphase - the nuclear membrane has completley broken down and there is a spindle at each pole of the cell the chromosomes line up on the equator of the cell

Anaphase - the centromeres have divided and each chromatid is pulled apart and become a chromosome

Telophase - the chromosomes have reached the poles and a nuclear membrane forms around them. Chromosomes uncoil and the cell divides.

2.5.6

What does Mitosis have a role in?

Growth

embryonic development

tissue repair 

asexual reproduction