CP 2 The Cell Flashcards
What are the general characteristics of a living organism
- Exhibits growth and development into highly ordered forms
- Made of one or more cell
- Building instructions stored in DNA
- Maintain homeostasis
- Requires energy (ATP)
- Reproduce on their own
- Evolve
- Die
How does Life exhibits emergent properties
Individual molecules come together to become increasingly organized and complex
what is Central dogma of molecular biology
- Life based on DNA->RNA->Protein
- DNA can store tremendous amnts of info
- DNA storage could last over 1000 years
Are viruses a form of life?
- No, needs DNA,
- Not universally accepted though
TF Water is the solvent of life and why?
T
- Dissolves more molecs than any other solvent
- Dissolves polar and charged molecs
What r the 4 types of macromolecs
- Carbs
- Lipids
-proteins - Nucleic acids
what are carbs
polymers of sugars
are lipids polymers ?
No, don’t see alternating units of polymers
what are proteins
polymer of amino acids
what are nucleic acids
polymers of nucleotides
How r polymers formed
- Several monomers go thru polymerization (Using dehydration synthesis) to form polymers
what is depolarization
polymers broken down using hydrolysis
what r the 4 structures of amino acids
Primary structure - amino acid chain
Secondary structure – ex) α-helix, β-sheet
tetrinary structure - folding
Quatrinary structure – assembling with other proteins into a complex
what r 2 polymers of carbohydrates
Amylose
Cellulose
Why are cells so small
- Surface are needs to be sufficient for transportation of molecs thru membrane
- Lrger volumes req more surface area+structural support
- If the SA is not large enough to meet the demands of cell V, the cell will stop growing
- High SA, low vol—Low SA, High Vol
What are the 3 characteristics of Microscopy
- Resolution: distinguish details of a specimen or sample
- Magnification: Observed size/actual size(higher magnification increases resolution
- Contrast: Higher contrast give more details (sharpness)
what is resolution
ability to distinguish 2 objects as separate
what is Magnification
Observed size/actual size(higher magnification increases resolution
what is Contrast
Higher contrast give more details (sharpness)
how does a light microscope work
- Uses lenses to bend light up to 100-fold
- Used to view specimens in natural colour
- Uses chemical dyes and fluorescent labelling to increase contrast
what are the 4 types of light microscope
- Brightfield
- Darkfield
- Phase-contrast
- Differential Interference Contrast (DIC)
how does a darkfield microscope work
- Provides dark background
- Light is directed at the specimen at an angle, not directly at the specimen
Provides better contrast
How does a phase contrast microscope work
- Microscope captures phase changes in the light
Higher detailed images
How does a DIC microscope work
- Similar to phase contrast
Gives a 3D type look
What do both Prokaryotic and Eukaryotic have
- Plasma membrane
- Cytoplasm
- Chromosome
- Ribosome
- DNA
What is an electron Microscope+how is it better
-Uses electrons to illuminate specimen
-Provides greater magnifications and resolutions
What is a Transmission Electron Microscope(TEM)
- Uses very thin tissue slices
- Chemically fixed and dehydrated
- Stained with heavy metals
- Cannot see living cells
What is a scanning election microscope
(SEM)
- Scatter electrons over surface to get depth+3D image
- Also uses chemicals+ dehydrated + heavy metals
what is Fluorescence Light microscopy
- Uses high intensity shorter wavelength light to hit specimen
- Specimen then emits low wavelength fluorescence
- Also uses fluorescence(dyes, proteins, pigments(from specimen))
what is Confocal Fluorescence microscopes
- Increases contrast by capturing very thin slices of the specimen
Does this by passing light thru a tiny pinhole
what is the endomembrane system
- Divides eukaryotic cells into functional structural compartments
- Components are either continuous or connected via transfer by vesicles
what does the endomembrane system consist of
- Nuclear envelope
- ER
- Golgi apparatus
- Lysosomes
- Vacuoles
- Plasma membrane
what is a ribosome
- Composed of 2 subunits
- Site of protein synthesis
What is the endoplasmic reticulum
- Continuous of nuclear envelope
2 types (rough and smooth) - Rough ER
○ Ribosomes attached
○ Synthesizes proteins - Smooth ER
○ No Ribosome attached
○ Synthesize lipids, phospholipids and steroids, not proteins
○ Regulates carbohydrate metabolism in some cells
○ Stores calcium
○ Detoxifies drugs and toxins
what is the ER Lumen
- Further modification, polishing and folding of proteins occur here after they have been made by the ER
- Then they are transferred to plasma memb. by vesicles
what is the Golgi apparatus
- Shipping and receiving centre
- Consists of flattened membranous sac
- Modifies product of ER-chemically modifies proteins
- Manufactures macromolecs
○ Eg) glycolipids
The Surface facing the nucleus in the Golgi apparatus is called
ceasface
What is the Trans Golgi network (TGN)
vesicles leaving with molecs from transface
what are cisternae
Parallel layers of golgi sacs
The Surface facing the membrane in the golgi is called
transface
what are lysosomes
- Digestive system
- Sacs of hydrolytic enzymes
- Formed by budding from Golgi complex
what is Autophagy
○ Degradation process of which lysosome removes dysfunctional components
○ Allows orderly degradation and recycling cellular components
what is phagocytosis
○ Cell uses plasma memb. to engulf a large particle
- Common in cells of immune systems
what do central vacuoles in plants do
- Storage
- Maintain internal turgor pressure(pressure of water in cell)
- Maintain acidic pH
- Contains enzymes that break down unwanted cellular molecs
- Provide chemical defence
what are vacuoles
- Membrane bound sacs
- Common in plant and fungal cells
- Food vacuoles formed by phagocytosis
what do central vacuoles do
- Storage
- Maintain internal turgor pressure(pressure of water in cell)
- Maintain acidic pH
- Contains enzymes that break down unwanted cellular molecs
- Provide chemical defence
What are Semi autonomous organelles
“Originated from ancient prokaryotic symbiotes, evolved to rely on host cell and can not longer live independently”
What r 2 examples of semi autonomous organelles
mitochondria
chloroplast
What is the mitochondria
- Found in animal and plant
- Site of cellular respiration
- Most atp produces here
- Most O2 is primarily used in mitochondria
what is a chloroplast
- Found in only plants and algae
- Photosyntheis occurs
- Produces O2
what are some traits of semi autonomous cells
- Have their own genome(small circular plasmids)
- Have their own ribosome
- Can replicate on their own
- Have double membranes
- Size= prokaryotic microbes
what do chloroplast and mitochondria have in common
- make apt
- have internal membranes
- have folding to increase surface area for energy
- Double membrane
- Inner memb. 2 compartments
○ Intermembrane space
○ Mitochondrial matrix
what do chloroplast and mitochondria NOT have in common
- Photosynthesis vs cellular respiration
- Uses light+CO2 vs Sugars and O2
- Pancakes = Thylakoids vs Folds = cristae
What are 3 examples of other plastids
- Chromoplast
- Leucoplasts
- peroxisomes
What is the function of the cytoskeleton
- cell shape
- cell polarity
- cell division
- cell movement and migration
- intracellular transport and cytoplasmic organization
What does the Cytoskeleton do
organizes structures and activities in the cell
What is a microtubule
hollow tube formed from tubulin dimers
what is a tubulin dimmer
- 1 alpha tubulin + 1 beta tubulin = tubulin dimmer
- these dimmers come together spirally to form a tube
What are the main functions of a microtubule
- Maintenance of cell shape
- Motility (cili and flagella)
- Chromosome movements in cell division
- Organelle movements
Tf Microtubules have positive and negative ends
T, gives them polarity
TF Microtubules are always lengthening and shortening
T, (polymerization and depolymerization)
Which end of the microtubules does the lengthening and shortening occur
+ve end
Tf microtubules grow from the cells wall
F, they grow from a centrosome near the nucleus
how are spindle apparatuses formed
Centrosome has a pair of centrioles, each with 9 couplets(9+2 complex) of microtubules arranged into a ring spindle apparatus, the microtubules then extend from centrioles.
What is a microfilament
- Actin Polymer
- protofilaments form helix
- have + and - end
- grow and shrink( polymerization and depolymerization)
- growth and shrinkage happens at +ve and -ve ends
What are the functions of a microfilament
- maintenance and changing of cell shape
- muscle contraction
- Cytoplasmic streaming (move shit around in cell)
- Cell motiity
- cell division
What is an intermediate filament
think collagen
- Polymers of intermediate filament proteins
- varied composition depending on cell type
- don’t have polarity dynamic
- can be both in and out of cell
What r the functions of an intermediate filament
- maintenance of cell shape (tension elements)
- Anchorage of nucleus to certain other organelles
- formation of nuclear lamina(line inner surface of nuclear envelope in animals)
what are motor proteins
Bind filament to 1 end and cargo to the other and walk along cytoskeletal filaments (except intermediate) carrying vesicles and other organelles
what are the 3 motor protein families
- Myosins - found in muscle cells - walk along MFs
- Kinesins - walk along MTs
- Dyneins - walk along MTs
How do microfilaments work in muscle contractions
- Muscle contraction = sliding between actin and myosin filaments
what do cilia and flagella have in common
Theyre made from:
- Centrioles
○ Forms basal bodies which anchor cilia or flagella
○ 9 doublets of microtubules that forms ring
○ Centre has 2 microtubules
(called 9+2 complex)
○ Dynein motor proteins slide microtubules over each other, Produce movement
whats the difference between cilia and flagella
- Quantity (thousands of cilia, 1-8 flagella)
- Length (cilia much shorter)
- Beating pattern (cilia random and flagella like propellor)
- Cilia only found in euk cells, flagella found in both
- 2 types of cilia (non motile and motile)
3 types of flagella (bacterial, archaeal, eukaryotic)
What is the function of the animal ECM
○ Adhesion(keep cells close to each other) ○ Support
○ Protection from external forces
○ Regulate shape
○ Movement
○ Cell division
○ Intercellular comms
TF animal ECMs are mostly carbs
F, are mostly proteins/glycoproteins.
TF the composition of animal ECMs are widely variable depending on the cell type
T
What does the animal ECM consist of
- Collagen (Skin, bones, tendons, most abundant)
- Fibronectin (link between integrin and ECM
- Integrin(receptor protein on membrane)
- Proteoglycan complex (Polysaccharide molec with proteins and carbs connected)
What are intercellular junctions
Structures formed by integral membrane proteins - connected to the actin cytoskeleton - by linker proteins
what do tight junction proteins do
○ Hold plasma membrane of 2 cells tightly attaches
○ Regulate what passes thru the between of the plasma membranes
what do desmosomes do
○ Anchoring junction
○ Very common in muscle cells
○ Made of intermediate filaments
○ Fasten cells together into strong sheets
What do gap junctions do
○ Allows cell to cell communication
○ Provide continuous link to cytoplasm’s of connecting cells
○ Pathways for exchange of solutes and other stuff between neighbouring cells
what are the 3 types of intercellular junctions
Tight
Desmosomes
Gap
TF the cell wall is what distinguished plant and animal cells
T, almost every cell except for the animal cell has a cell wall
what does the plant cell wall do
- Provides protection
- Structure maintenance
- Made of cellulose fibers embedded in polysaccharides and proteins
- Maintain turgor pressure
How many layers of the cell wall are there and what are the called
3, Primary, Secondary, plasma membrane
2 characteristic of the primary cell wall
- thin and flexible
- contains plasmodesmata (channel between cells)
What r 2 characteristics of the secondary cell wall
- Between plasma memb and primary wall
- Has lignin which makes it very rigid
What is the thin layer between primary walls of adjacent cells - enriched with pectin
The middle Lamella
what is pectin in the middle lamella
the glue
What is a contractile vacuole
It fills with water from the cytoplasm and then discharges this externally by the opening of contractile vacuole pores
