Cell Basics Flashcards
(106 cards)
1
Q
Eukaryotes (8)
A
- Protists, Fungi, Plants, Animals
- Cell wall present in fungi and plants
- Nucleus
- Multiple linear chromosomes
- ribosomal subunits 40S and 60S
- Membrane-bound organelles
- mitosis/meiosis
- Steroids in plasma membrane (for rigidity)
2
Q
Prokaryotes (8)
A
- Bacteria, archaea
- Cell wall present
- no nucleus, nucleoid
- Predominately circular DNA (plasmids)
- Ribosomal subunits 30S and 50S
- no membrane-bound organelles
- No mito - ETC on cell membrane
- no steroids in membranes (rely on protein network and cell wall for rigidity)
- binary fission
3
Q
Endosymbiotic theory
A
the theory that Eukaryotic cells evolved through symbiosis of prokaryotes (similarities between mitochondria, chloroplasts and prokaryotic cells)
4
Q
similarities between mitochondria, chloroplasts and prokaryotic cells (3)
A
- multiply through binary fission
- contain circular DNA
transport - proteins called porins
5
Q
Order Nucleus, mitochondria, ribosome, and chloroplasts from largest to smallest DIAMETER (µm)
A
Nucleus - Chloroplasts > Mitochondria > ribosome
6
Q
Order Nucleus, mitochondria, ribosome, and chloroplasts from largest to smallest DENSITY (µm
A
ribosome - chloroplasts > Nucleus > mitochondria
7
Q
What are the differences between archaea and bacteria?
A
Archeae:
- More genetically similar to eukaryotes than bacteria
- some can survive very high temperature
- Membrane lipids have more ether bonds (more resistant than ester bonds)
Bacteria:
- membrane lipids have ester bonds
- some are pathogenic but others have a mutualistic symbiotic relationships (gut bacteria)
- cell walls contain peptidoglycans
- have flagella and fimbriae
8
Q
What are shared traits between Archaea and bacteria?
A
- Similar shape
- Same ribosomal density
- binary fission
- singular circular chromosome
- phospholipids
- most have cell walls
- found in animals, soil, oceans
9
Q
Cell organelles underwen a differential centrifugation process in a sucrose solution. the speed of the centrifugation increased. At the end, where would the ribosomes appear in relation to the mitochondria?
A
the ribosomes would be further from the surface than the mitochondria
(in centrifugation, the smaller and denser molecules are pushed downward)
- if one or the other, an equation is needed
10
Q
is ribosome an organelle?
A
No
11
Q
from what is driven our undertanding of the plasma membrane?
A
the Fluid mosaic model
12
Q
Why is the phospholipid bilayer amphipathic?
A
hydrophobic tails on the inside and hydrophilic heads on the outside allows the membrane to be both hydrophobic and hydrophilic qualities
13
Q
What is the structure of a phospholipid?
A
a glycerol backbone (organic) + 1 Phosphate group (inorganic) and 2 FA chains
14
Q
types of proteins in membrane
A
- peripheral (tend to move around a lot)
- integral (completely embedded - more stuck, or transmembrane)
15
Q
What are some peripheral proteins on the membrane?
A
Surface proteins and some glycoproteins
16
Q
What are some integral proteins on the membrane?
A
Completely embedded (tend to move less) and transmembrane
17
Q
What are examples of transmembrane proteins ?
A
- some glyproteins
- transport proteins (channels)
- membrane receptors
18
Q
What is the role of glycoproteins on the membrane?
A
Carbs and protein that form H bonds to reinforce the cell’s structure, and membrane receptors
19
Q
Types of membrane receptors?
A
- Ligand-gated ion channel receptors
- Enzyme-coupled receptors
- G-protein coupled receptors
20
Q
The Lipid raft theory
A
dense regions of the plasma membrane heavy in Cholesterol and serve as protein signaling platforms (can move across the membrane and can be broken down into smaller rafts)
21
Q
Why is the lipid raft theory controversial?
A
because it can only be observed indirectly using fluorescent microscopy
22
Q
What are the types of passive transport?
A
- Simple diffusion
- Facilitated diffusion
- Osmosis
- Filtration
23
Q
What are the types of active transport?
A
- Primary
- secondary
- Exocytosis
- Endocytosis
24
Q
What are the types of endocytosis?
A
- Pinocytosis (cell-drinking)
- Receptor-mediated
- phagocytosis
25
What is passive transport?
Molecules move in and out of the cell according to concentration gradient --> Kinetic Energy, no ATP needed
26
What is simple diffusion?
Molecule simply passing from one side of the membrane to the other
27
What is facilitated diffusion?
a transport protein helps the molecule go from one side of the membrane to the other - Important for:
polar hydrophilic molecule beacuse hard to go across the lipid layer.
and large molecules (glucose)
28
Carrier protein
a type of transport protein where the moleucle binds to the protein and is specific enough, taken in, and released on the other side.
29
Channels
simple transport proteins where no binding required and less specific
30
Osmosis
simple transport involving a solvent - usually water - across the permeable membrane, depending on the concentration of the molecules, through aquaporins - not guated, structural only.
31
Are aquaporins the only way for water to get across the membrane?
no can also simply difuse across but when needed in large quantities, will go through aquaporins.
32
Osmolarity
Used to describe solute concentration
C= n/V --> Solute concentration / volume solvent
(blood osmolarity: 290 mOSm/L)
33
Osmolality
Used to describe solute concentration
Solute concentration per mass solvent.
if too high, body wil secrete anti-diuretic hormone (to remove excess water/volume)
34
Tonicity
Used to describe solute concentration
Measure of osmotic pressure gradient between two solutions
Only influenced by solutes that can't cross the membrane.
35
Isotonicity
the solute concentration is the same inside and outside of the cell
36
Hypertonicity
the solute concentration is greater outside of the cell, water follows out and causes cell to shrivel = crenation
37
Hypotonicity
The solute concentration is higher inside of the cell, water follows and causes cell to swell/lyse
38
Filtration
water and small molecules are forced through a selective permeable membrane due to hydrostatic pressure (heartbeat, kidney, liver...)
39
What is active transport?
it is the movement of molecules against the concentration gradient, using ATP
40
Primary active transport
makes direct use of ATP to push molecules against their concentration gradient.
41
Secondary active transport
uses indirect forms of ATP to push molecules and is gradient.
(powers other mechanisms and as a consequence, pushes molecules in and out)
42
Na-K pump
uses ATP to move 3 Na+ out and 2 K+ in, ATP is converted to ADP and the energy of the cleavage is used to drive the pump
43
Electrochemical potential driven 2nd active transport
the gradient created by the gradient causes the Na to go back in (along gradient) but transport channel will carry another molecule in or out using the energy of Na
44
Countertransporter or antiport
2nd active transport, uses the gradient created by the Na K pump to transport Na back in and a molecule out using that same energy
(number of ions don't need to be the same (Na+ and Ca2+)
45
Co-transporter or symport
2nd active transport, uses the gradient created by the Na K pump to transport Na back in and a molecule in using that same energy (SGLT: Na+/Glucose)
46
Exocytosis
Larger molecules are transported to cell from extracellular environment via vesicles (water to get across the lipid layer)
47
Trafficking
the movement of the vesicle up to the membrane
48
tethering and docking
when the vesicle makes contact with the membrane and becomes attached
49
Complete Fusion
the vesicle fuses with the membrane and becomes a part of it, and content is released outside - the vesicle is lost, components can be reused to make future vesicles
50
Kiss and run (KR fusion)
vesicle gets close to the membrane, creates a nm sized hole, releases content, and pops back in, the vesicle can be used again for other purposes.
51
Endocytosis
Bringind large molecules into the cell, also uses vesicles.
52
Pinocytosis - cell drinking/liquid endocytosis)
molecules are taken in in the water they are floating in. Membrane invaginates and pinches off and bring in the particles in vesicles. Lysosomes bind and break through using hydrolytic enzyme mixture - Non specific
53
Receptor-mediated endocytosis / clatherin dependent endocytoss
Specific. receptor is on the outter membrane and adaptor proteins inside, to facilitate communication and signaling, in this case AP2 will bind clatherin to form vesicles, breaks off within the cell. Clatherin and adaptor proteins de-assemble can be reused for other purposes.
54
Phagocytosis / cell-eating
Cell - phagocyte - moves to find something to eat. the shape changes as the molecule binds to receptors of phagocyte. Formation of a phagosome, then a phagolysosome (binding of lysosome), digestion, and release of microbial products through exocytosis.
55
Cell theory (4)
1) All living things are made of cells
2) Cell is basic functional unit of life
3) Cells arise from preexisting cells
4) Cells carry genetic info in the form of DNA
56
Are viruses considered living organisms?
no, because they do not carry replication machinery and rely on host cells to replicate (obligate intracellular pathogens) and may contain RNA as their genetic info
57
Nucleolus
site of rRNA transcription, processing, and assembly
58
Nuclear membrane in Eukaryotes is a double membrane?
yes
59
Mitochondria membranes
outer and inner membrane, the intermembrane space is where the proton motive force establishes to power ATP synthase.
60
origin of the mitochondria
thought to have evolved from an anaerobic prokaryote engulfing an aerobic prokaryote through symbiosis
61
mDNA
Mitochondrial DNA, contained in mito, double stranded, and containes some of their own genes independently of the one in the nucleus
replicates via binary fission
62
Cytoplasmic and extranuclear inheritance
concerns certain organelles that contain genetic matertial outside of the nucleus. Since the egg will contain the organelles, in this case, it is a maternal inheritance.
63
Lysosomes
sequester hydrolytic enzymes
64
Rough ER
connected membranes, continuous with the nuclear envelope, dotted with ribosomes thus translated proteins can be directly secreted into the RER lumen.
65
Smooth ER
connected membrane, continuous with nuclear envelope, no ribosomes, lipid synthesis and drug detox
also transports proteins from RER to golgi
66
Golgi Apparatus
stacked membrane bound sacs, it can modify cellular products and deliver them directly to their destination
67
peroxisomes
breaks down very long chains of FA through beta oxidation, produces hydrogen peroxide and containes enzymes to break it down.
some synthesis of phospholipids and some enzymes of the pentose phosphate pathway.
68
What is the role of Cytoskeletons
provides structure and highways for transporting materials
69
What are the types of cytoskeletons (3)
- microfilaments
- microtubules
- intermediate filaments
70
Microfilaments
- polymerized actin
- resistant to compression and fracture
- can be used to generate force for movement by interacting with myosin
- involved in cytokinesis by forming the cleavage furrow in a ring
71
Microtubules
- hallow polymers of tubulin
- involved in mitosis by attaching to kinetochores and centromeres to separate sister chromatids
- involved in cell transport as it is the primary pathway for motor proteins (kinesin, dynein)
- cilia and flagella
- centrioles
72
Cilia
Moves material along surface of the cell
73
Flagella
Moves cell itself
74
What is the structure of cilia and flagella in eukaryotic cells ?
9 pairs (doublets) of tubulin in outer ring and 2 central microtubules
75
What are centrioles ?
microtubule organizing centers
found in centrosomes
during mitosis, they migrate to opposite poles of the dividing cell and organize the mitotic spindle
76
What is the structure of centrioles?
9 triplets around a hollow center
77
What is the role of intermediate filaments?
cell-cell adhesion, cytoskeleton integrity maintenance, anchors organelles, can withstand a lot of tension, makes cells rigid.
78
Eukaryotic cell types
muscle, nervous tissue, epithelial tissue, connective tissue
79
What is the role of epithelial tissue?
lines cavities, protects, involved in secretion, absorption, sensation...
compose the basement membrane
Can be simple, stratified, and pseudostratified
can be cuboidal, columnar, and squamous
80
What is the role of connective tissue?
contributes to the stroma (the support structure) - bone, blood, cartilage, tendons, ligaments, adipose...
81
Shape Classification of prokaryotes
- Bacilli (rod-shaped)
- cocci (spherical)
- spirilli (spiral)
82
Aerotolerant Anaerobes
can't use O2 but not harmed by its presence
83
Prokaryotic cell structure
- envelope; cell wall (controls movement of solutes across it) + cell plasma membrane, can be gram + or -
- flagella
- plasmids
84
Gram +
has a thick layer of peptidoglycan, absorbs crystal violet stain and becomes purple
85
Gram -
has a thin layer of peptidoglycan, absorbs counterstain but not crystal violet and becomes pink
in addition to the envelope (cell wall + plasma membrane) they have an extra outer membrane made of phospholipids and lipopolysaccharides
86
Flagella structure
composed of a filament (hollow structure of flagellin) + basal body (motor, does the turning) + hook (links filament and basal body
87
prokaryotic plasmids
acquired from external sources, not necessarily for survival - not part of the genome - but could be beneficial and have some evolutionary benefits + increase bacterial diversity
88
Binary fission
Asexual reproduction, cell copy DNA, segregate copies to opposite ends, protein machinery invaginates at the midline of the cell.
Bacteria of 1 colony are identical
89
Exponential growth (phases of growth)
lag phase
exponential phase (log phase)
stationary phase (carrying capacity, limited resources)
death phase
90
Types of prokaryotic recombinations
- Transformation: integration of foreign genetic material into host genome
- Conjugation (F- to F+)
- Transduction: a virus can carry genetic material from one bacteria to the other and infect other bacteria
- Transposons: genetic material capable of inserting and removing themselves from genome (both euka and prokaryotes)
91
Does all the genome gets transferred in prokaryotic conjugation?
No, it can break off, and as a result the genetic info near the end does not get transferred. But the High freq of recombination contains the F factor.
92
Conjugation
sexual reproduction, genetic info is transferred from F+ cell (contains Fertility/sex factors) in the plasmid to F- cell. A conjugation bridge is formed and allow one strand of the plasmid to enter the F- cell. Replication occurs in both cells and a double stranded plasmid exists in both cells. F- cell is now converted to F+ and can go on and conjugate with another cell.
93
Viruses structure
Capsid + genetic material (RNA, DNA, ds, ss) + sometimes a phospholipid envelope (with viral proteins)
94
Are envelope viruses easier to kill?
yes because heat sensitive, detergents, dissiccation
95
Viruses are obligate intracellular parasites?
yes, they do not have their own machinery, and need a host cell to reproduce.
96
Bacteriophages
don't enter the host cell. Release their genetic material only, using their tail fibers to anchor to cell membrane.
97
Positive sense RNA viruses
genome can be directly translated by ribosomes of host cell.
98
Negative sense RNA viruses
these viruses have RNA replicate to produce the complementary RNA strand for protein synthesis.
99
Retroviruses
these viruses have reverse transcriptase to produce DNA from ssRNA, DNA integrates the host genome and becomes replicated and transcribed as if host genome's. The host cell becomes indefinitely infected.
100
Virions
viral progeny using host machinery
101
progeny release
either through lysis and host dies
| or through fusing with the cell membrane (similar to exocytosis) - cell survives and continue to be used by virus.
102
Lytic cycle
virus makes max use of host machinery until virions lyse the cell and are released.
103
Lysogenic cycle
virus genetic material integrates cell genome as a prophage and is replicated as the host cell replicates. Can revert to a lytic cycle.
104
Prions
infectious proteins that cause protein misfolding (usually alpha to beta)
105
Viroids
short single ssRNA that infects plants --> binds to RNA sequence to silence genes in plant genome, disrupting cell processes
106
Chemotaxis
the movement of prokaryotic cells in response to a chemical stimulus
