MCAT Biology (Princeton Review)

Maltose

Glucose + Glucose

Sucrose

Glucose + Fructose

Lactose

Glucose + Galactose

Glycogen

Animal glucose storage

Starch

Plant glucose storage

Cellulose

Plant structure

Saturated Fatty Acids

-Single bonds

-Solid at room temp.

Unsaturated Fatty Acids

-Double bonds

-Liquid at room temp.

Terepenes

Built from multiple isoprene units

Cholesterol

-In cell membrane

-Steroid precursor

-Bile salts

Catalysts

-Stabilize the transition states

-Reduce the activation energy

Competitive Inhibition

-Binds at active site

-No change in Vmax

-Increases Km

Non-Competitive Inhibition

-Binds at allosteric site

-Decreases Vmax

-No change in Km

Uncompetitive Inhibition

-Binds at allosteric site of ES complex

-Decreases Vmax

-Decreases Km

Mixed Inhibition

-Binds at allosteric site of E along or ES complex

-Decreases Vmax

-Varied effects on Km

Glycolysis

-Occurs in the cytosol

-O2 in not needed

PCD/Krebs Cycle

-Occurs in the mitochondrial matrix

-O2 is indirectly needed

Electron Transport Chain/Oxidative Phosphorylation

-Occurs in the mitochondrial inner membrane

-O2 is directly needed

Fermentation

Pyruvate --> Ethanol (yeast) or Lactic Acid (muscle)

Glycogenesis

-High blood glucose

-Insulin produced

-Glucose converted to glycogen

-Stored in liver and lesser extent in muscle

Glycogenolysis

-Low blood glucose

-Glucagon produced

-Glycogen converted to glucose in the liver

Pentose Phosphate Pathway

-Produces NADPH

-Reducing power

-Fatty acid synthesis

-Eliminate reactive oxygen species

-Ribose-5 phosphate --> nucleotide synthesis

Fatty Acid Oxidation

-Occurs in the mitochondrial matrix

-Linked to acetyl-CoA

-Conezymes used are FAD and NAD+

-2 ATP input makes lots of energy

Fatty Acid Synthesis

-Occurs in the cytosol

-Starting Materials: acetyl-coA and malonyl-CoA

-Coenzyme used is NADPH

-Requires a lot of energy

Ketogenesis

-During long term starvation

-Blood glucose is low

-Fatty acids oxidized increase levels of acetyl CoA

-Acetyl CoAs react together to form ketone bodies

-Ketone bodies enter the brain and are reconverted to acetyl-CoA (primary source of energy for the brain during starvation)

Pyrimidines

-Cystosine

-Thymine

-Uracil

Pyramids are sharp so they "CUT" you

Purines

-Adenine

-Guanine

AG (silver) is "pure"

A-T Base Pairing

2 hydrogen bonds

G-C Base Pairing

3 hydrogen bonds

DNA Gyrase

Helps prevent supercoiling in prokaryotes

Heterochromatin

Inactive, tightly bound

Euchromatin

Active, loosely bound

Centromere

-Region on chromosome (in the middle)

-Mitotic spindle attaches here

-Holds replicated DNA together during mitosis

Central Dogma

DNA replication --> Transcription into RNA --> Translation into proteins

Start Codon

-AUG = Methionine

Stop Codons

-UAA (you are annoying)

-UGA (you go away)

-UAG (you are gross)

Human Genome

-46 chromosomes

-23 chromosome pairs from each parent

Polymerase Errors

1.) Point mutations

2.) Small repeats

3.) Insertions/deletions (small, frameshift)

Endogenous Damage (Reactive Oxygen Species or Physical Damage)

1.) Oxidized DNA

2.) Crosslinked bases

3.) Physical damage

4.) These can lead to polymerase errors

Exogenous Damage (Radiation or Chemicals)

1.) UV radiation = pyrimidine dimers

2.) X-rays = double-stranded breaks and translocation

3.) Chemicals = can lead to physical damage or to intercalation and those polymerase errors

Transposons

1.) Insertions/deletions (large)

2.) Inversions

3.) Duplications

Point Mutations

-Single base pair change

1.) Missense

2.) Nonsense

3.) Silent

Missense Mutation

-Codon for amino acid becomes new codon for new amino acid

-Change in the amino acid results

Nonsense Mutation

-Codon for amino acid becomes STOP codon

-Shortened protein results

Silent Mutation

-Codon for amino acid becomes new codon for same amino acid

-No effect

Frameshift Mutations

-Insertions/deletions

-Changes the reading frame

X-Rays

Cause double strand breaks

UV Radiation

-Causes pyrimidine dimers

-Repaired by white light

DNA Replication

1.) Semiconservative

2.) 5' to 3'

3.) Requires a primer

4.) Requires a template

Helicase

Unwinds DNA

Primase

Puts down the RNA primer

Topoisomerase

-Cuts DNA

-Relaxes supercoiling

DNA Polymerase

-Replicates DNA

-Proofreads

-Removes primer

Ligase

Links Okazaki fragments

DNA Polymerase III

-High processivity

-Fast 5' to3' polymerase and 3' to 5' exonuclease

-Adds nucleotides at ~400bp downstream of ORI

-This is the main replicating enzyme

-No known function in DNA repair

DNA Polymerase I

-Low processivity

-Adds nucleotides at RNA primer

-Slow 5' to 3' polymerase and 3' to 5' exonuclease

-Also a 5' to 4' exonuclease to remove primer

-DNA excision repair

DNA Polymerase II

-5' to 3' polymerase and 3' to 5' exonuclease

-Back up for DNA Pol III

-DNA repair

DNA Polymerase IV and V

-Error prone 5' to 3' polymerase activity

-DNA repair

Telomerase

-Lengthen telomeres

-Carries it's own RNA template

-Reverse transcriptase activity

DNA

-Double stranded

-Thymine

-Deoxyribose

-Double helix

-One type

RNA

-Single stranded

-Uracil

-Ribose

-Lots of different shapes

-Many different types

rRNA

Ribosomal RNA

mRNA

Messanger RNA

tRNA

Transfer RNA

hnRNA

Heterogenous nuclear RNA

miRNA and siRNA

Micro RNA

Transcription

-Is the primary point of regulation for translation

-Promoter: strong = affinity for RNA pol get a lot of RNA, weak lower affinity for RNA pol get less RNA

-DNA Binding Proteins: repressors and enhancers

Transcription (Prokaryotes)

-Transcription and translation happen at the same time

-No mRNA processing

-Polycistronic

-1 RNA polymerase

Transcription (Eukaryotes)

-Transcription and translation happen in different places

-mRNA processing (5' G-cap, 3' poly-A tail, splicing)

-Monoscistronic = "one mRNA, one protein"

-3 RNA polymerases (RNA Pol 1 = rRNA, RNA Pol II = mRNA, RNA Pol III = tRNA)

Wobble Base Pairs

G,U, I at the 5' end of anticodon

Subunits of Ribosome (Prokaryotes)

-Large: 50S

-Small: 30S

-Total: 70S

Subunits of Ribosome (Eukaryotes)

-Large: 60S

-Small: 40S

-Total: 80S

A Site

New amino acid is added to this site

P Site

Growing site of the protein

Post-Translational Modification: Protein Folding

-Some inherent (polar-polar, non-polar to non-polar)

-Some helped by chaperone proteins

Post-Translational Modification: Covalent Modification

-Phosphorylation

-Glycosylation

-Disulfide Bridges

Post-Translational Modification: Processing

Removing a portion of protein to activate it

Virus

-Obilgate intracellular parasite

-Protein + nucleic acid

-Capsid protein

-Can't be both RNA and DNA

Viral Life Cycle

1.) Attachement (Adsorption) - specific, not yet infected

-Injection (Penetration) - infected

Lytic Cycle

-Transcribe and translate the viral genome

-Replicate viral genome

-Lysis of host and release of new viral particles - put holes in bacterial cell wall

Lysogenic Cycle

-Integrate viral genome with host genome

-Normal host activity, including reproduction

-Excision and lytic cycle

Productive Cycle

-Like lytic cycle but no lysis

-Budding

-Animal viruses ONLY

-Get coated in lipid bilayer envelope

RNA Dependent RNA Polymerase

-Reads RNA (RNA Dependent)

-Makes RNA (RNA Polymerase)

RNA Dependent DNA Polymerase

-Reads RNA

-Makes DNA

-Reverse transcriptase

Prions

-No DNA/RNA

-No cell membrane

-No organelles

-Very small

-Extremely stable (heat resistant, acid resistant, detergent resistant)

Mutant Prions

-Arise by mutation

-Be inherited

-Be ingested

Viroids

-Circular RNA

-No capsid

-Don't code for proteins

-Base pair with existing RNA

Bacillus Bacteria

Rod shaped

Coccus Bacteria

Sphere shaped

Spirella Bacteria

Spiral shaped

Gram Positive Bacteria

-Thick peptidoglycan cell wall

-Purple stain

Gram Negative Bacteria

-Thin peptidoglycan cell wall

-Pink stain

Mesophile

Medium temperature living condition

Thermophiles

Hot temperature living condition

Psychrophile

Cold temperature living condition

Obligate Aerobe

Need oxygen to survive

Facultative Anaerobe

-Use oxygen to survive

-Without oxygen survive through fermentation

Tolerant Anaerobe

-Does not prefer oxygen but will not die

-Prefers no oxygen to live on fermentation

Obligate Anaerobes

-Will die in the presence of oxygen

-Survive without oxygen through fermentation

Phototroph

Converts sunlight to ATP