This is a type of secretion, the vesicle fuses with the plasma membrane and its contents are released. This is called "exocytosis".

The theory of spontaneous generation tried to explain the occurance of organisms like maggots, mould and bacteria in rotting food. Pasteur's experiments falsified this theory.

Under the microscope there is little change during interphase.
However interphase is a very active phase of the cell cycle with many processes occurring in the nucleus and cytoplasm. (It is subdivided into G1, S, G2 phases of the cell cycle)
DNA replication occurs during the S-phase.

Membrane proteins are diverse in terms of structure, position in the membrane and function.
Peripheral proteins are attached to the membrane but found on its surface.

Know how to idenfity the organelles in eukaryotes and draw their compartmentalised structure.
The rER has parallel membranes covered in dots, which are ribosomes, used for making proteins, for secretion from the cell.

Chloroplasts are distinctive because they have stacks of membranes inside, called grana, which hold the chlorophyll that absorbs light.

If you look closely at X, it points to the cell wall, outside the plasma membrane, it is close to the plasma membrane, but not touching the chloroplast.

The pale area below Y is the vacuole.

Organelle Y is a mitochondrion, you can tell this by its size, and the presence of membranes inside.

The resolving power, or resolution, is the ability to separate objects, to produce separate images of two objects.

Exceptions to cell theory are : multinucleated striated muscle the giant single celled Acetabularia algae?
Also, organisms consisting of only one cell carry out all functions of life in that cell. e.g. Paramecium, Chlorella.

Multicellular organisms have properties that emerge from the interaction of their cellular components. (Emergent properties)

Specialised tissues can develop by cell differentiation in multicellular organisms.

Differentiation involves the expression of some genes and not others in a cell.

Many transmembrane proteins are involved in transport of molecules across membranes. These can either provide a sort of molecular pore through which ions or molecules can pass (facilitated diffusion), or they can use ATP to actively move molecules, even against the concentration gradient (active transport).These are just two examples, transport can also occur by simple diffusion through the phospholipid bilayer, or by endocytosis.

Endocytosis is the process where a substance is surrounded by the plasma membrane which forms a vesicle inside the cell that then moves into the cytoplasm, separating from the plasma membrane.

The mitochondria provide evidence supporting endosymbiosis because they have:

• a double membrane
• 70S ribosomes
• DNA

Comment: Convert 1.2 mm into μm by multiplying x 1000 = 1200 μm (so that both units are the same). Then you can see that 0.6 x 2000 = 1200. Or use the formula Magnification = Image size/true size. If the photograph is larger than the cell, the magnification could not be 0.5x which would make it smaller. Eliminate obviously incorrect answers.

There are actually four types of membrane transport which are required in DP Biology, Simple diffusion, facilitated diffusion, osmosis and active transport.

The lack of a membrane bound nucleus (nucleoid) classifies a cell as prokaryotic.

Channel proteins are used for facilitated diffusion down the concentration gradient.

The saline drip must be isotonic to human blood to not cause water gain or loss from tissues.

The irregular sizes and insolubility of hydrophobic membrane proteins indicated that they could not be a surface layer as proposed by Davison-Danielli. This was confirmed by fluoresecent antibodies showing that proteins were both within and on the membrane.