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Cell and Molecular Biology Ch1- Cells Cheat Sheet (DRAFT) by

Cells: Fundamental Units of Life, based on Ch 1 of Essential Cell Biology, 5th ed. Bruce Alberts et al.

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

Cell Theory

Cells are the basic structural & functional unit of life.
Viruses do not qualify as living.
All living organisms are composed of cells.
No cellular struct­ures,
All cells arise from pre-ex­isting cells.
don't metabo­lize,
Sponta­neous generation does NOT occur.
not motile,
don't reproduce w/o a host cell


Double phosph­olipid bilayer membrane (nuclear envelope)
Biggest organelle in most cells
Ancestral prokaryote membrane folded in on itself, trapping DNA and protecting it

Nucleus cont.

The nuclear envelope is very restri­ctive
Contains most eukaryotic DNA (some DNA in chloro­plasts and mitoch­ondira)
Organizes DNA with chromo­somal territ­ories separated by proteins
Nucleolus is the site of ribosomal RNA (rRNA) synthesis and assembly
Protein structures and RNA can fit through nuclear pores to leave the nucleus
rRNA is the most abundant form of RNA, and is part of the ribosome

Golgi Apparatus

Functions to process, sort, and ship molecules synthe­sized in ER
"Post office­" of the cell
Made up of Cisternae - all separate flattened membranes for vesicular transport
Cis side- ["sa­me"] side facing ER
Trans side- ["op­pos­ite­"] side facing away from ER
Vesicular transport can be tracked in a laboratory with a Green Fluore­scent Protein (GFP)


["br­eaking body"]
Acidified organelle specia­lizing in digestion
degrades material via endocy­tosis
(bring into cell, phagoc­ytosis is a type of endocy­tosis)
enzymes work in the acidified enviro­nment to digest
they break down intrac­ellular materials
Aid in Autophagy- ["se­lf-­eat­ing­"]
recycle things like mitoch­ondria that are 'expired' to use material for other metabolic functions

Cell Diversity

Measured in microm­eters
1x103µm = 1mm
1x106µm = 1m
bacteria= 1-10 µm
plant/­animal= 10-100 µm
round, rod, or spiral shape
shape is linked to function
Form Fits Function
Aerobic= needs oxygen
Anaerobic= without oxygen or oxygen is toxic
Prokaryote vs.
>no membrane bound organelles
>me­mbrane bound organelles
>Do­mains Bacteria & Archaea
>Domain Eukaryota
>Eu­kar­yotes stress compar­tme­nta­liz­ation, using organelles with different functions and specia­lized roles.
>Pr­otists are included in Eukaryota, being single celled Eukary­otes.


Composed of rRNA and protein - rRNA does the actual transl­ating
Performs protein synthesis (trans­lation)
Possessed by ALL cells
Not membrane bound
2 different popula­tions in eukary­otes:
Free (cytos­olic)- floating around, makes cytopl­asmic proteins
Bound to endopl­asmic reticulum (ER)- makes ER proteins, cell membrane proteins
Exists inside chloro­plasts and mitoch­ondria (to translate cpDNA and mtDNA)
cpDNA= chloro­plast DNA
mtDNA= mitoch­ondrial DNA

Smooth ER

site of synthesis of membrane lipids (phosp­hol­ipids, choles­terol)
Ca2+ storage for muscle cell contra­ction
> Ca2+ is a signalling molecule, kept in the smooth ER until needed for muscle contra­ction


Site of cell respir­ation
(citric acid cycle, e- transport)
has endosy­mbiotic origins:
>double phosph­olipid bilayer membrane
>an­cestral eukaryote with nuclear envelope and ER phagoc­ytized an ancestral prokaryote that was good at cell respir­ation
Matrix- aqueous solution inside mitoch­ondria
Cristae- inner membrane of mitoch­ondria
this increases surface area for cell respir­ation to occur
Key to initiation of apoptosis- programmed cell death
occurs when there is DNA damage, metabolic stress, or oxidative stress


the cell's 'muscles and bones'
Filame­ntous proteins- 'bones', structure, support, shape
Motor proteins- 'muscles', contra­ction, cell movement
>co­ntr­ibutes to eukaryotic cell shape
>co­ntrols all aspects of eukaryotic cell motility


Cell Wall
Cell Membrane
possessed by most organisms: bacteria, protists, fungi, plants
possessed by every cell
provides structure and shape,
functions as: control entry and exit from cell (semi-­per­mea­ble),
protection against hypotonic enviro­nment,
cell commun­ica­tion,
very porous to permit passage of nutrients.
adhesion to other cells (anchored with protein comple­xes).
Phosph­olipid bilayer moves laterally and fluidly, composed of small pieces

Endopl­asmic Reticulum

The ER is a physical extension directly connected to the outer membrane of the nuclear envelope.
> proteins in the nuclear membrane can diffused directly into the ER
Lumen= space in between membrane of ER

Rough ER

"­Rou­gh" because of ribosomes on the surface
site of synthesis for:
endome­mbrane system proteins
secreted proteins
Endome­mbrane system: ER, golgi, lysosome, cell membrane
Secreted proteins function outside cells (eg. antibo­dies)
>nu­cle­us/­rou­gh/­smooth ER -> vesicle -> golgi -> vesicle -> lysosome or cell membrane


Site of photos­ynt­hesis (CO2 to glucose etc. using light energy)
(plants, photos­ynt­hetic protists)
Thylakoid- flat stacks of membrane, possess photos­ynt­hetic enzymes
>site of light reaction
Stroma- aqueous solution within chloro­plast
>site of dark reacti­on/­Calvin cycle
Double phosph­olipid bilayer membrane
endosy­mbiotic origins: photos­ynt­hetic prokaryote became organelle in eukaryote

Evidence of Endosy­mbiosis

Mitoch­ondria and Chloro­plasts possess:
>double phosph­olipid bilayer membrane
>mtDNA (mitoc­hon­drial DNA)
>cpDNA (chlor­oplast DNA)
>di­vision that mimics that of bacteria (binary fission)
>di­vision is completed when 'half-­life' of mitoch­ond­ria­/ch­lor­oplast is spent