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CELLULAR AND MOLECULAR BIOLOGY FINAL EXAM
NEWEST 2025 ACTUAL EXAM 250 QUESTIONS AND
CORRECT DETAILED ANSWERS WITH RATIONALES
(VERIFIED ANSWERS) |ALREADY GRADED A+
Robert Hooke
discovered cells by looking at them through a microscope
Matthias Schleiden
concluded that all plants are made of cells
Theodor Schwann
concluded that all animals are made of cells
Rudolf Virchow
proposed that all cells originate from another cell
-Virchows triad!
Properties of living cells
1) genetic information stored in 1-D sequences in DNA code for linear
sequences of RNA
and 3-D structures of proteins
2) cell components self assemble
3) proteins need signals to move to right place
4) cell components move by diffusion, pumps, motors
5) cells respond to messages from the enironment
,2
3 domains of lifebacteria, archaea (prokaryotes), eukaryotes
Prokaryotes
-No nuclei, loosely organized, small, cell wall + membrane
-Cytoplasmic component contains DNA, RNA, proteins
(EX. bacteria, archaea)
Gram positive
have thick peptidoglycan layer above inner membrane which traps dye
between the strands, causing them to show up in the gram test. (EX.
Staphylococcal, Streptococcal)
Gram negative
have very thin peptidoglycan layer situated between inner and outer
membranes. (EX. E.Coli, Salmonella)
Eukaryotes
-DNA in membrane enclosed nucleus
-Specialized cells
-Lack cell walls
-Compartmentalized interior
-Cytoskeleton
(EX. plants, animals, fungi, protozoa)
Janssen Brothers
Invented the first compound microscope in 1595 using a two lens
eyepiece.
,3
Light Microscope
uses visible light and a system of lenses to magnify images of small
objects, good for bacteria and mitochondria (500nm)
Electron microscope
- Scanning E.M. (SEM) - produce 3D structure imagery
- Transmission E.M. (TEM) produce 2D cross-sections
-> sample must be very thin, requires special preparation for E.M.
Dyes/Antibodies -Antibodies labeled with fluorescent dye detect specific
target molecules (antigen), allow us to visualise proteins and lipids in
fixed cells
-Live cell imaging allows us to visualise cells in real time
Plasma membrane
provides cell boundary and prevents movement of materials in to and
out of the cell.
Composed of lipids and proteins
Organelle membrane divide cytoplasm into compartments
Properties of membranes
1) form flexible continuous barriers
2) selectively permeable
, 4
Composition of membranes
1) Proteins
- provide membrane function
2) Lipids (phospholipids, cholesterol)
- provide structure and permeability barrier
Both proteins and lipids have a covalently linked oligosaccharide
(glycoproteins, glycolipids)
Phospholipid
-Amphiphatic (polar headgroup + hydrophobic tail)
-Held together by non-covalent forces
Major Phospholipids
1) Phosphoglycerides
2) Sphingolipids (EX. Sphingomyelin which has sphingosine instead of
glycerol)
Liposomes
-have phospholipid bilayer
-used experimentally in drug delivery + DNA/RNA delivery into cells
Phospholipid movement
Phospholipids rotate or exchange in the lateral plane of the membrane,
and flip flop from one leaflet to another
CELLULAR AND MOLECULAR BIOLOGY FINAL EXAM
NEWEST 2025 ACTUAL EXAM 250 QUESTIONS AND
CORRECT DETAILED ANSWERS WITH RATIONALES
(VERIFIED ANSWERS) |ALREADY GRADED A+
Robert Hooke
discovered cells by looking at them through a microscope
Matthias Schleiden
concluded that all plants are made of cells
Theodor Schwann
concluded that all animals are made of cells
Rudolf Virchow
proposed that all cells originate from another cell
-Virchows triad!
Properties of living cells
1) genetic information stored in 1-D sequences in DNA code for linear
sequences of RNA
and 3-D structures of proteins
2) cell components self assemble
3) proteins need signals to move to right place
4) cell components move by diffusion, pumps, motors
5) cells respond to messages from the enironment
,2
3 domains of lifebacteria, archaea (prokaryotes), eukaryotes
Prokaryotes
-No nuclei, loosely organized, small, cell wall + membrane
-Cytoplasmic component contains DNA, RNA, proteins
(EX. bacteria, archaea)
Gram positive
have thick peptidoglycan layer above inner membrane which traps dye
between the strands, causing them to show up in the gram test. (EX.
Staphylococcal, Streptococcal)
Gram negative
have very thin peptidoglycan layer situated between inner and outer
membranes. (EX. E.Coli, Salmonella)
Eukaryotes
-DNA in membrane enclosed nucleus
-Specialized cells
-Lack cell walls
-Compartmentalized interior
-Cytoskeleton
(EX. plants, animals, fungi, protozoa)
Janssen Brothers
Invented the first compound microscope in 1595 using a two lens
eyepiece.
,3
Light Microscope
uses visible light and a system of lenses to magnify images of small
objects, good for bacteria and mitochondria (500nm)
Electron microscope
- Scanning E.M. (SEM) - produce 3D structure imagery
- Transmission E.M. (TEM) produce 2D cross-sections
-> sample must be very thin, requires special preparation for E.M.
Dyes/Antibodies -Antibodies labeled with fluorescent dye detect specific
target molecules (antigen), allow us to visualise proteins and lipids in
fixed cells
-Live cell imaging allows us to visualise cells in real time
Plasma membrane
provides cell boundary and prevents movement of materials in to and
out of the cell.
Composed of lipids and proteins
Organelle membrane divide cytoplasm into compartments
Properties of membranes
1) form flexible continuous barriers
2) selectively permeable
, 4
Composition of membranes
1) Proteins
- provide membrane function
2) Lipids (phospholipids, cholesterol)
- provide structure and permeability barrier
Both proteins and lipids have a covalently linked oligosaccharide
(glycoproteins, glycolipids)
Phospholipid
-Amphiphatic (polar headgroup + hydrophobic tail)
-Held together by non-covalent forces
Major Phospholipids
1) Phosphoglycerides
2) Sphingolipids (EX. Sphingomyelin which has sphingosine instead of
glycerol)
Liposomes
-have phospholipid bilayer
-used experimentally in drug delivery + DNA/RNA delivery into cells
Phospholipid movement
Phospholipids rotate or exchange in the lateral plane of the membrane,
and flip flop from one leaflet to another
