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Cell Biology Cheat Sheet (DRAFT) by

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Animal Cells

Organelle Functions

Forms Centrioles for Mitosis & Myosis
Gets rid of waste products
Nuclear Pore
Transports messenger RNA
DNA + protei­n-> Chromatid
Smooth E.R.
Lipid synthesis, Vitamin + Mineral accumu­lation
Rough E.R.
Protein synthesis
messenger RNA joins with RNA to make aminoacid chains
Site of respir­ation
Golgi Body
Packaging of products in a cell
Nucleo Plasm
Hydro-­ske­leton to hold chromasome
Ribosomal RNA production
Nuclear Membrane
Holds nucleo­plasm in place

Types of Cells

Eukaryotic Cells
Plant and animal cell with a nucleus and membra­ne-­enc­losed organe­lles.
Prokar­yotic Cells
Unicel­lular organism without a nucleus or membrane enclosed organe­lles.

Cell Membrane

Surface Carboh­ydrate: used in cell recogn­ition and commun­ica­tion.
Channel Protein: allow micro-­mol­ecules to enter and exit the cell.

Structure of Chloro­plasts

Chloro­plast Structure

A thylakoid is a membra­ne-­bound compar­tment inside chloro­plasts and cyanob­act­eria. They are the site of the light-­dep­endent reactions of photos­ynt­hesis.
A stacked membranous structure within the chloro­plasts of plants and green algae that contains the chloro­phyll and is the site of the light reactions of photos­ynt­hesis. The saclike membranes that make up grana are known as thylak­oids. See more at chloro­plast.
The colorless fluid surrou­nding the grana within the chloro­plast. Dark-Phase takes place here

Structure of Mitoco­ndria

Mitoch­ondrial cristae are folds of the mitoch­ondrial inner membrane that provide an increase in the surface area. This allows a greater space for processes that happen across this membrane.
the substance occupying the space enclosed by the inner membrane of a mitoch­ond­rion; it contains enzymes, filaments of DNA, granules, and inclusions of protein crystals, glycogen, and lipid.

Structure of Mitoco­ndria


Passive Cell Transport

The movement of molecules from and area of high concen­tration to an area of low concen­tra­tion, until an equili­brium is reached.
Movement of fresh water (with low to no soluble components dissolved in it) from an area of high concen­tration to an area of low concen­tration through a semi/s­ele­cti­vel­y-p­erm­eable membrane.
Channel Protein
The Channel Protein in the cell membrane allows the passive transport of larger molecules that cannot diffuse through the membrane.
Carrier Protein
A charged molecule, such as ions, regardless of size cannot diffuse through the membrane. Microm­ole­cules attaches to carrier protein which then travels through the membrane and releases the molecules inside.

Osmosis in Plant Cells

Osmosis in Plant Cells

If tonicity inside the cell > tonicity outside the cell: Cell becomes turgid as water diffuses into the cell, turning the cell rigid and giving the plant structure
If tonicity inside the cell = tonicity outside the cell: Cell loses some of the turgor pressure. Overall plant structure and integrity compro­­mised
If tonicity inside the cell < tonicity outside the cell: Cell becomes plasmo­­lysed as the water diffuses out of the cell. Cell membrane and cytoplasm detaches from Cell Wall.

Osmosis in Animal Cells

Osmosis in Animal Cells

If tonicity inside the cell > tonicity outside the cell: Cell takes on so much water that there is a possib­ility of it becomeing lysed, or bursting.
If tonicity inside the cell = tonicity outside the cell: Cell behaves normally
If tonicity inside the cell < tonicity outside the cell: Cell becomes shrivelled

Cell Cycle

DNA Replic­ation

Splitting of DNA Strand
DNA strand is unwound and split into two halves by the enzyme helicase, hence creating a structure called a replic­ation fork
Leading Strand
DNA polymerase binds to the leading strand (5'-3' beginning of the fork to the end) and reads the DNA in the 3' to 5' direction, adding nucleo­tides in the 5'-3' direction
Lagging Strand
RNA primers attach to points of the lagging strand. Okazaki fragments are able to be attached to the lagging strand using these primers as markers. RNA primers are removed by enzymes, and DNA polymerase replaces the gaps left by the primers.
Recomb­ination of Strands
DNA strand is re-wound.

Active Transport

Molecules (usually macro-­mol­ecules) can be made to move against the concen­tration gradient (i.e. beyond an equili­brium) this requires the expend­iture of energy ATP (Adeno­sin­e-T­ri-­Pho­sph­ate).

Endocy­tosis - Entering The Cell

Movement of small macro molecules and liquid­s/F­luids through a cell membrane enclosed in a vesicle
Phagoc­ytosis is the same as pinocy­tosis but involves larger molecules



The transport of material out of a cell by means of a sac or vesicle that first engulfs the material and then is extruded through an opening in the cell membrane


Light Phase
Dark Phase
Light energy is used to split a water molecules into oxygen and hydrogen (Photo­lysis)
3 CO2 molecues are introduced into the stroma and are added to the Hydrog­en+ATP molecules to make 1 G-3-P (Glyce­ral­dehyde 3-phos­phate)
The oxygen escapes the cell as a bi-pro­duct. The H+ ion binds with a nearby electron to form a hydrogen atom, The energy released is used to create ATP
This process of converting CO2 to G-3-P. To create glucose, this is repeated to produce 2 G-3-P molecules, a total of 6 CO2 to make 1 Glucose
Photos­ynt­hetic reactions are affected by:
The surface area of the chloro­plast, thylakoid membrane etc.
The concen­tration of reactants
The presence of Catalysts
Temper­ature and pH

Respir­ation - Step 1 - Glycolysis

Step 1. Glycolysis
Occurs just outside the mitoch­ondria. Glucose is split into 2 pyruvate molecules, requiring 2ATP and producing 4 ATP. Net gain of 2ATP
Pyruvate molecules are converted in to acetayl coenzyme A, which then enter the matrix space
(Bacteria only undergo this one step as they have very little energy requir­ements)
In anaerobic condit­ions, this produces ethanol and CO2 in plants and bacteria, while animal cells produce lactic acid and CO2

Respir­ation - Step 2 - Krebs Cycle

Acetyl co-enzyme A joins to a carbon carrier molecule and loses carbon as CO2
Hydrogen atoms are lost also and they in turn lose their elections -> net 2ATP molecules are produced

Respir­ation - Step 3 - Electron Chain

Hydrogen ions formed in Krebs cycle bind to O2 and produce water. Energy released is used within the cristae to produce ATP. During the entire cycle, there is a net production of 38 ATP