Cell Structures and Metabolism Flashcards by sophie rosen

Q

3 major divisions of the living world

A

bacteria
archaea
eukaryotes

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Q

plasma membrane function

A

selective barrier and enables cells to maintain integrity to function as a coordinated chemical system

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Q

nucleus function

A

store house of genetic information

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Q

endoplasmic reticulum function

A

lipid and protein biosynthesis and intracellular Ca2+ store

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Q

rough ER function

A

Membrane bound ribosomes which allows for co-translational translocation of protein peptides chains into the ER concomitant with protein synthesis

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Q

smooth ER function

A

Regions of ER that lack ribosomes. Regions of smooth ER from which transport vesicles bud off and carry newly synthesized proteins and lipids to the Golgi are known as transitional ER. In cells that specialize in lipid metabolism the synthesis occurs in the smooth ER. In muscle cells the expanded smooth ER is specialized for Ca2+ storage and is called the sarcoplasmic reticulum.

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Q

golgi function

A

major site of carbohydrate synthesis, sorting and dispatching of products made in the ER

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Q

mitochondria function

A

energy metabolism (oxidative phosphorylation and krebs cycle). also has a distinct mitochondrial DNA genome separate from nuclear DNA

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Q

lysosomes function

A

site of intracellular digestion of macromolecules, very heterogenous in terms of morphology, hydrolytic enzymes in lysosomes are all acid hydrolases

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Q

prokaryotic vs. eukaryotic cells

cell membrane?

A

prokaryote: yes
eukaryote: yes

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Q

prokaryotic vs. eukaryotic cells

nucleus?

A

prokaryote: no
eukaryote: yes

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Q

prokaryotic vs. eukaryotic cells

chromosomes?

A

prokaryote: 1 (not a true chromosome)
eukaryote: many

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Q

prokaryotic vs. eukaryotic cells

ER?

A

prokaryote: no
eukaryote: yes

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Q

prokaryotic vs. eukaryotic cells

vesicles?

A

prokaryote: yes
eukaryote: yes

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Q

prokaryotic vs. eukaryotic cells

golgi?

A

prokaryote: no
eukaryote: yes

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Q

prokaryotic vs. eukaryotic cells

mitochondria?

A

prokaryote: no
eukaryote: yes

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Q

prokaryotic vs. eukaryotic cells

cytoskeleton?

A

prokaryote: yes/no
eukaryote: yes

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Q

prokaryotic vs. eukaryotic cells

ribosomes?

A

prokaryote: yes (smaller)
eukaryote: yes (larger)

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Q

prokaryotic vs. eukaryotic cells

size?

A

prokaryote: 1-10 microns
eukaryote: 10-100 microns

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Q

fimbriae (or pili) function

A

attachment to surfaces

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Q

flagella function

A

motility

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Q

LPS function

A

activate inflammatory responses

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Q

capsule function

A

may play a role in dental caries

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Q

gram positive

A

thick peptidoglycan
single inner membrane
teichoic acid

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gram negative

thin peptidoglycan inner and outer membrane LPS associated with outer leafet of outer membrane

why is gram positive purple-blue?

the thick peptidoglycan prevents crystal violet from being washed out with ethanol

why is gram negative pink?

the thin peptidoglycan allows crystal violet to wash out

peptidoglycan is comprised of chains of alternating

N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) sugars crosslinked by oligopeptides

transpeptidase

responsible for the crosslinking of peptidoglycan

transpeptidase is inhibited by

the antibiotic amphicilin

mechanism of amphicilin

kills gram positive bacteria (because they have a thick peptidoglycan layer) by preventing the formation of peptidoglycan

mitochondria is the site of

oxidative phosphorylation and ATP production within the cell

mitochondria contains a small

circular genome

the bulk of proteins found in mitochondria come from the

nuclear genome, not mitochondrial genome

glycolysis occurs in the cytoplasm to generate

pyruvate

how is pyruvate transported into the mitochondrial matrix?

it crosses the outer mitochondrial membrane through the voltage gated anion channel not clear how it crosses the inner membrane

once pyruvate enters the matrix it is then converted to

acetyl-coA by the pyruvate dehydrogenase complex

acetyl-coA transfers its acetyl group to oxaloacetate to form

citrate

NADH binds to

complex 1 to generate 3H+

FADH binds to

complex 2 to generate 2H+

concentration gradient causes the ATP synthase to

spin and form ATP

each proton that is pumped through the channel can generate

1 molecule of ATP

fatty acid beta-oxidation generates much more

NADH

net product in the cytosol from glycolysis from 1 glucose

2 pyruvate 2 NADH 2 ATP

net product in the mitochondria from the pyruvate dehydrogenase complex and citric acid cycle

2 pyruvate= 2 acetyl coA + 2 NADH | 2 acetyl coA= 6 NADH + 2 FADH2 + 2 GTP

net product in the mitochondrion

2 acetyl coA= 8 NADH + 2 FADH2 + 2GTP

net products from oxidation of one molecule of palmitoyl CoA in the mitochondrion (fatty acid oxidation and citric acid cycle)

1 palmitoyl coA= 8 acetyl coA + 7 NADH + 7 FADH2 | 8 acetyl coA= 24 NADH + 8 FADH2 + 8 GTP

net products from oxidation of one molecule of palmitoyl CoA in the mitochondrion

1 palmitoyl coA= 31 NADH + 15 FADH2 + 8 GTP

glycolysis has a net yield of

2 ATPs and 2 NADH molecules

citric acid cycle produces

2 ATP 8 NADH 2 FADH2

NADH yields

3 ATP

FADH2 yields

2 ATP

a molecule of glucose can therefore produce a net yield of

30-32 ATP

gatty acid beta-oxidation of palmitate (16C sugar) yields

31 NADH 15 FADH2 8 GTP

palmitate yield is therefore

131 ATP 2 ATP used in the initial activation therefore, 129 ATP

however, a more precise yield of NADH and FADH2 is

2.5 NADH 1.5 FADH2 because realistically we will not have 100% effectiveness

biofilm

a cooperating community of microorganisms within a matrix that is attached to a surface

biofilms develop in any

fluid filled environment containing microorganisms that are subjected to stress or fluid flow

dental biofilms exist on

the tooth surfaces and mucosal surfaces of the oral cavity

explain the production of biofilms & microbial stage cycle

a pellicle forms within seconds and attachment of pioneering bacteria conditioning (largely gram positive cocci (streptococci)). within minutes, cross-linkning via fusoformbacterium species occurs as a log phase of expansion as the bacteria multiply and divide. after hours, stationary phase occurs with predominately gram negative bacteria. after days, nutrient supply diminishes and bacteria die.

the pellicle forms from proteins in the

saliva orGCF

the pellicle serves as a

conditioning film for attachment of the initial colonizing bacteria

why do some people get cavities and others dont?

diversity difference in the distribution on bacteria and biofilm composition

the bacteria within the colonies communicate with one another via

chemical signals

these microcolonies also adjust their pH and can have varying nutrient supplies which can induce

novel gene expression within the bacteria in the biofilm

fluid channels allow for movement of

nutrients, waste products, metabolites, enzymes, and o2

fluid channels are

porus channels

carcinogenic bacteria produce extracellular polysaccharides from

sucrose

sucrose is split into

glucose and fructose

glucose can be built into homopolymers of glucose called

glucans | such as mutan (water insoluble) and dextran (water soluble)

fructose can be built into homopolymers called

fructan | consisting of beta 1,2 and beta 2,6 linkages

these extracellular polysaccharides serve as a

nutritional source for bacteria, which supports further adhesion and subsequent accumulation of plaque

sucrose is highly

soluble

sucrose diffuses rapidly into the

plaque biofilm where it serves as a substrate for production of the extracellular polysaccharides and acids

the main causal agents for caries are (3)

streptococcus mutans lactobacillus casei lactobacillus fermentum

saccharolytic bacteria derive energy from

glycolysis

in anaerobic metabolism,

pyruvate generates lactic acid, which lowers the pH, acidity dissolves enamel, and eventually forms carries

biofilms on the tooth surface will form a

dental plaque

once dental plaque becomes calcified, it is termed

calculus (tartar)

calculus can only be removed through

dental cleaning, rock hard

in patients with healthy dentition and no periodontal disease, most bacteria in the dental biofilms are

gram-positive

the bacteria mainly ferment sugars to the final end product of

lactic acid (saccharolytic microbiota/fermentation)

the production of lactic acid results in low pH, which can result in

demineralization of the tooth enamel and dentin, resulting in a carie

asaccharoyltic bacteria derive energy from

amino acids

free amino acids can be

deaminated or reduced

alanine deamination to

pyruvate and NH3 to form lactate which forms ammonium lactate

reduction of glycine forms

acetate and NH3

reduction of cysteine forms

propinate HS NH3

reduction of alanine forms

propinate H2O NH3

constituents of dental plaque (3)

ammonium acetate ammonium propinate ammonium butyrate

dental plaque occurs on the

tooth and gingival margin because there is a higher pH, so the tooth is not demineralized

dental calculus further promotes

assacharolytic fermentation

as cysteine and methionine are fermented, one of the end products is

hydrogen sulfide

hydrogen sulfide causes

oral malodor | often associated with periodontal disease

you dont see caries in the gingival margin because

the high concentration of ammonia ions (high pH)

saliva is composed of

99% contains Na, K, Ca, Mg, bicarbonate, phosphates, immunoglobulin proteins, enzymes, mucins, and nitrogenous products sushc as urea and NH3

3 types of saliva

serous mucos mixed serous and mucos

serous saliva is the main product of the

parotid glands

mucos saliva is the main product of the

minor glands

mixed serous and mucos is the main product of the

sublingual and submandibular glands

saliva functions (5)

``` lubrication and protection buffering action and clearance maintenance of tooth integrity antibacterial activity taste and digestion ```

how much saliva do we produce

750-1000 mL per day

where does all the saliva go?

we swallow it

GCF

gingival crevicular fluid

how much GCF do we produce

1-2 mL per day

where is GCF secreted

into the gingival sulcus

gingival sulcus

between the surface of the tooth and the free margin of the epithelium lining of the gingiva

functions of GCF (4)

cleansing the sulcus improve adhesion of the epithelium to the tooth antimicrobial properties antibody defense of the gingiva

beneath healthy gingival sulcus, the gingival crevicular fluid provides an environment that is rich in proteins and fermentation of amino acids to produce

ammonia (asaccharoyltic bacteria/fermentation)

high ammonia concentration causes a high pH region that prevents dental caries from developing but can lead to the

precipitation of calcium and phosphate on a dental biofilm (plaque) and eventually the formation of a dental calculus