Final Study Guide- Cumulative Material Flashcards
(35 cards)
explain the major differences between eukaryotic and prokaryotic cells
-Eukaryotic cells found in animals, plants, fungi
-have organelles.
-prokaryotic cells only in bacteria and archaea
-do not have organelles or true nucleus
Describe the functions of the major components of prokaryotic cells
-cell (cytoplasmic) membrane: thin sheet of lipid and protein that surrounds cytoplasm
-bacterial chromosome or nucleoid: condensed
DNA molecules; contains genetic info and codes for all proteins
-ribosomes; protein synthesis sites
-cytoplasm: water-based solution filling the cell
Describe the difference between Gram-positive and Gram-negative cells
Gram Positive
-many thick layers of peptidoglycan cell wall
-lack an outer membrane
-has lipoteichoic and teichoic acid which increases wall flexibility
Gram Negative
-thin peptidoglycan cell wall
-has outer membrane with lipopolysaccharide
-has porin proteins
Describe how eukaryotes evolved
Endosymbiotic hypothesis - identify the lines of evidence
[indicates origins of mitochondrion and chloroplast]
Mitochondria evolved from a Rickettsia
Chloroplast evolved from a cyanobacteria
-nucleus has a double membrane
-Mitochondria have their own cell membranes, just like a prokaryotic cell does.
-DNA — Each mitochondrion has its own circular DNA genome, like a bacteria’s genome, but much smaller.
-Reproduction — Mitochondria multiply by pinching in half — the same process as by bacteria; chloroplast also independently divided
-mitochondria and chloroplast act as separate entities & have their own circular DNA (similar to bacterial chromosomes)
-mitochondria and chloroplast have their own ribosomes
Describe the functions of the common external structures found on eukaryotes.
Eukaryotic flagella
-10x larger than prok. Flagella.
-has a cell membrane
-9 pairs of microtubules surrounding 2 single microtubules (figure 5.4)
-whips back and forth
-find these in some protozoa, some algae (not in fungi).
Cilia
-shorter, hair-like (same as eukaryotic flagella, just numerous, covering entire cell)
-only found in one type of protozoa called ciliates & animal cells.
-movement
Glycolalyx layer (sticky surface layer)
-made of polysaccharides
-can be a slime layer or capsule
-for sticking, not movement. Prevents dehydration/water loss.
Cell wall [protozoa & animal cells do not have a cell wall]
Fx: structural support and shape
-algae cell walls- made of cellulose
-fungi cell walls- made of chitin
Cell membrane- selective permeability
Sterols, sugars, proteins, phospholipids
In animal cells- cholesterol
In fungal cells- ergosterols
Describe the general structure of a virus, both inside and outside.
Outer:
Capsid, may have an envelope
Capsid made of capsomers; helical and icosahedral
With dna/rna in capsid = nucleocapsid
Can be naked (no envelope) or enveloped (surrounded by membrane)
~~~Most viruses have the envelope [made of phospholipids and embedded proteins] 13/20
~~Viral spikes can be inserted into the envelope, or be in the capsid in a naked virus [Viral spikes- responsible for attaching to a host cell- determined host range [which organisms can it affect] - determines tropism]]
inside:
Core - nucleic acid molecules either DNA or RNA, may contain matrix protein enzymes
nucleic acid types inside: dsDNA, ssDNA, dsRNA, ssRNA
ds= double-stranded, ss = single-stranded
Describe the steps of viral replication.
Adsorption- using viral spikes, will attach to host cell; glycoprotein attachment
Penetration- being engulfed or [direct fusion only w/ enveloped viruses, envelope fuses with]
Uncoating- the dissolving of vesicle, envelope, and capsid
Synthesis- making all the parts of virus [capsomers, nucleic acid copying, spikes…]
Assembly- bringing all parts together, capsid forms from capsomers, nucleocapsid, spikes inserted in membrane or nucelocapsid
Release- virion buds off
Describe what a prion is and what makes it so unique.
infectious protein that can replicate; associated with the slow virus spongiform encephalopathies of humans and animals
[a misfolded protein that can transmit its misfolded shape onto normal variants of the same protein. Prions are the causative agent of several transmissible and fatal neurodegenerative diseases in humans and other animals]
-lacking nucleic acids
BSE mad cow disease
-scrapie -CJD -vCJD -Kuru -fatal familial insomnia–
What are the different ways microbes bring molecules into their cells? Which requires energy?
endocytosis - requires energy
group translocation - requires energy
ion pumps- requires energy
facilitated diffusion - no energy
osmosis - no energy
Draw a population growth curve and explain what is happening at each step.
-label axis if asked to draw curve/graph
Bottom X axis - time
Side Y axis: living cells
4 phases
-Lag- looks like nothing is happening; cell is gearing up for cell division; it is copying its DNA which takes long time…DNA replication
-Log rhythmic/ log/ exponential— growth; optimal rate of growth will continue if there is nutrients & space…
-Stationary — growth levels out, division slowed, cell death is increasing; population remaining the same; running out of food and space
-Death – due to build-up of waste products (toxic, poop, salt…)— does not go to Zero
—doubling time is 30-60 minutes
-E coli is usually 30 minutes to reproduce
Describe the ways scientists count the number of microorganisms in a sample.
Viable cell count: just counting living cells ; cannot figure out how many dead cells; accurate and cheap; can take at least a day
—CFU colony forming units
-turbidity- looking for cloudiness in a liquid culture = rough estimate how many dead and living cells there are
-spectrophotometer: passes light through culture/test tube; the more light reaches through, the less cloudy, and the less growth you have; relative scale of cloudiness to obtain doubling time; very inaccurate; dead and living cells.; immediate reading, $200
-Direct cell count- slide cytometer- more expensive-0- very accurate, immediate, but counting living and dead cells
-Flow cytometer– research labs; too expensive for hospitals; detect how big and dense cell is…laser beams shines on a single cell dropping out of a narrow tube..costs millions of dollars, extremely precise; differentiate between living and dead cells and different cell types
What are the inputs and outputs of glycolysis?
Input: 1 glucose and 2 ATP [ATP not required to be included… but you can]
Output: 2 ATP, 2 NADH, 2 pyruvic acids
What are the inputs and outputs of the TCA cycle?
Input: 1 ACETYL-COA per TCA cycle; 2 Acetyl CoA per glucose
Output: 4 CO2, 6 NADH, 2 ATP, 2 FADH2 PER GLUCOSE (cut in half for per turn)
What are the inputs and outputs of the respiratory chain?
Input: 10 NADH, 2 FADH2, 6 O2 (oxygen gas molecules)
Outputs: 34 ATP, 6 H2O
What are the inputs and outputs of fermentation?
Input: 1 glucose
Output: ethanol & Co2 OR lactic acid, … 2 ATP
Where does each step of cellular respiration take place in the prokaryotic cell?
Glycolysis- cytoplasm
TCA- cytoplasm
Electron transport- plasma membrane
Where does each step of cellular respiration take place in the eukaryotic cell?
Glycolysis- cytoplasm
TCA- mitochondrial matrix
Electron transport- mitochondrion cristae
What is the purpose of ATP synthase? How does it function and what does it need to function?
catalyzes the synthesis of ATP from ADP and phosphate
-it needs proton motive force to function, uses proton motive force and spins; creates covalent bond between ADP and inorganic phosphate
What does it mean to say DNA is a charged, polar molecule whose strands are anti-parallel and replicates in a “semi-conservative” fashion?
2 nucleic strands attached to each other by hydrogen bonds; basic acid is a nucleotide that consists of a pentose sugar, a phosphate, and a nitrogenous base
Antiparallel because strands are growing in opposite directions
According to the semiconservative model, after one round of replication, every new DNA double helix would be a hybrid that consisted of one strand of old DNA bound to one strand of newly synthesized DNA.
Name the six enzymes involved in DNA replication and describe, in order, what their roles are.
Gyrase: uncoiling supercoil + supercoiling
Helicase: unzipping the DNA helix
Primase: synthesizing an RNA primer
DNA Polymerase III: adding bases to the new DNA chain, proofreading the chain for mistakes
DNA polymerase I: removing RNA primers, replacing gaps between Okazaki fragments with correct nucleotides, repairing mismatched bases
Ligase: final binding of nicks in DNA during synthesis ; phosphodiester bonds
Describe the process of translation for prokaryotic organisms.
Take mRNA, using tools of ribosomes and tRNA to make proteins
-Initiation- small subunit binds, initiator tRNA, large subunit; have a shine-delgarno sequence found throughout the prok. mRNA.; several recipes/genes
-Elongation- next tRNA enters A site ; has anticodon that pairs with codon after start codon; ribozyme grabs first amino acid in P site or peptide and forms peptide bond to amino acid in A site; translocation: mRNA pulled thru by 3 nucleotides
termination
-Protein folding- this happens during elongation; happens as protein is being made; if protein loses its structure later, it can’t regain structure bc its being folded as it is being made
-Protein processing- changing protein to make it function- such as by adding functional groups to make enzymes function better, also maybe adding a cofactor like metal ions/vitamins, or in the case of insulin, needs to be cut and pieces removed to be functional
How does the entire process of transcription and translation differ between prokaryotes and eukaryotes?
Euk- only 1 gene per RNA; occurs in nucleus
Prok- several recipes per RNA; occurs in cytoplasm
Describe the five different types of point mutations and explain how they differ in the effects on the organism.
Wild-type (nonmutated) sequence [normal sequence found in most organisms] [THE BIG BAD CAT ATE THE FAT RED CAT]
Substitution mutation
Missense- usually, tolerated and fine.. 1 nucleotide change/ Small change; may or may not make huge impact on protein = [THE BIG MAD CAT ATE THE FAT RED BUG]
Nonsense- converts codon to stop codon; premature termination of protein synthesis; usually severe effect; [THE BIG BAD XXX (STOP)]
Inversion mutation- adjacent letters exchange places; can result in significant changes
Frameshift mutation– extreme effects; every amino acid after this is very impacted
-Insertion- addition of letter
-Deletion- deletion of letter
Reverse mutation- happens in mutants that change the mutated sequence back to wild-type
Silent mutation- change in nucleotide from one to another nucleotide that does not affect the primary amino acid sequence— no significant negative effect
Worst mutations- frameshift & nonsense
Best- silent (no bad effects)
Describe three methods other than sexual reproduction whereby organisms recombine their genetic sequences.
Conjugation- using protein bridge (pilus); sending a plasmid from one cell to another; plasmids are advantageous genes ex) metal resistance, toxin/enzyme production, iron uptake…
Transformation- done by competent cells; taking naked DNA from any source and trying it out; most cells are not naturally competent.
Transduction- involving viruses; accidental;
Transposons- happens in all organisms including our cells… individual DNA pieces that move around on their own inside our cells (some can replicate) they are single, jumping genes. Can move from 1 location to another, sometimes copy themselves, or escape and leave cell… = Mutation or change in DNA = genetic evolution
