BI151 Final Exam Review

Promoter (transcription)

Located at the start of the gene. Not transcribed or translated. Only there to orient polymerase.

We devoted a lot of time to the process of aerobic cellular respiration: glycolysis, Citric Acid cycle, and oxidative phosphorylation (via electron transport chain). Be familiar with the general processes of aerobic cellular respiration

Producing ATP with oxygen by breaking down glucose (36-38 ATP); occurs in the mitochondria

RNA elongation (transcription)

RNA peels off DNA and DNA fuses back together

mRNA Splicing

RNA splicing occurs - cuts out introns* and joins exons* introns = non-coding* exons = parts that are coded for or expressed*

Which feature of promoters can be found in both prokaryotes and eukaryotes?

TATA box

Imagine if there were 200 commonly occurring amino acids instead of 20. Given what you know about the genetic code, what would be the shortest possible codon length? Explain.

The shortest possible codon length would be 30 since with 20 commonly occurring amino acids, the shortest possible codon length is 3 which is 15% of 20 and 15% of 200 is 30.******

A scientist introduces a mutation that makes the 60S ribosomal subunit nonfunctional in a human cell line. What would be the predicted effect on translation?

Translation stalls after the initiation AUG codon is identified.

What is a chemical bond?

a force of attraction between two atoms

H bonds

a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other ex: HF

Be familiar with examples of aneuploidy in humans and be familiar with alterations of chromosome structure described in class.

abnormal # of chromosomes in cell cased by nondisjunction = a pair of chromosomes or sister chromatids fail to separate during any anaphase phase ex: trisomy 21, monosomy x, turner syndrome

carboxyl

acidic, adds H+ to soln

phosphate

acidic, adds H+ to soln

The ara operon is an inducible operon that controls the production of the sugar arabinose. When arabinose is present in a bacterium it binds to the protein AraC, and the complex binds to the initiator site to promote transcription. In this scenario, AraC is a(n) ________.

activator

proteins

amino acids proteins account for more than 50% of the dry mass of most cells* amino acid (20 diff ones) = building blocks all 20 can be grouped into 3* 1) nonpolar 2) polar 3) electrically charged only diff between all 20 is "R" component peptide bonds

What are anabolic and catabolic pathways?

anabolic = makes more complex things ex: photosynthesis* catabolic = breaks things down ex: cell respiration*

amino

basic, removes H+ from soln

Know the details of mRNA Processing covered in lecture

before mRNA goes to the cytoplasm after being transcribed... cap & tail are added RNA splicing occurs - cuts out introns* and joins exons*

fermentation vs aerobic cellular respiration

both use glycolysis and produce a pyruvate, which commits to either aerobic cellular respiration or fermentation based on presence or absence of O2

mRNA (structure and function)

(messenger) mRNA that is made during transcription, this is transcribed into RNA, then translated into protein

how does competitive inhibition affect enzyme activity?

decrease enz act

how does non-competitive inhibition affect enzyme activity?

decreases/stops enz act

DNA structure

double helix

ionic bonds

electrostatic forces that hold ions together in ionic compounds cation + anion ex: NaCl

Control of gene expression in eukaryotic cells occurs at which level(s)?

epigenetic, transcriptional, post-transcriptional, translational, and post-translational levels

What are the major differences between eukaryotic and prokaryotic cells?

eukaryotes have membrane-bound nuclei and organelles while prokaryotes don't

Specifically Regulation in Prokaryotes vs. Eukaryotes

eukaryotes: transcription RNA processing translation prokaryotes: mostly at transcription

lipids

fatty acids fats, steroids, phospholipids hydrophobic = they consist mostly of hydrocarbons which form nonpolar covalent bonds for hydrophilic = molecule needs to be polar or have charges ex: fats = have 2x more energy than starch 3 types of fats: saturated = tend to be solid, no double bonds, "unhealthy". saturated w/H unsaturated = tend to be liquid, double bonds, "healthier choice" ex: omega-3 fatty acids (good), palm oil (bad) trans = needs liquids to be solids, worst called trans bc goes through hydrogenation then there is a trans double bond

What are linked genes?

genes located on the same chromosome that tend to be inherited together

heterozygous

having two different alleles for a gene

homozygous

having two identical alleles for a gene

peptide bond (proteins)

how to find peptide bond = find C (needs to be double bonded to O, or carbonyl group) bonded to N

how does substrate concentration affect enzyme activity?

increasing substrate concentration also increases the rate of reaction to a certain point. Once all of the enzymes have bound, any substrate increase will have no effect on the rate of reaction, as the available enzymes will be saturated and working at their maximum rate

For example, what type of mutation would result from a codon change of ACC🡪AGC (the C is changed to a G)? Hint: find the amino acid that ACC codes for, and then determine the amino acid that AGC codes for.

missense mutation bc amino acid is changed

carbohydrates

monosaccharides sugars and short-term storage molecules (energy) dietary fiber fiber reduces risk of colorectal cancer quick energy source ex: monosaccharides (simple, non-complex) - glucose & fructose disaccharides = 2 mono's - maltose, lactose, sucrose polysaccharides = many mono's (non-simple, complex) - starch, glycogen, cellulose, chitin

how does co-factor affect enzyme activity?

need co-factor for enzyme activity

methyl

nonpolar, CH3

The RNA components of ribosomes are synthesized in the ________.

nucleolus

nucleic acids

nucleotides DNA - deoxyribose/deoxyribonucleic - stores genetic info - programs protein formation - made from 2 strands of nucleotides (ATGC) in a double helix pattern RNA - ribose/ribonucleic - translates language from nucleic acid to protein language! convert to protein, the link to protein single strand of nucleotides (AUGC) - U or uracile (RNA) and T (DNA) are one of the major differences between DNA & RNA

how does pH affect enzyme activity?

optimal pH = optimal enz act, any fluctuations = decrease

carbonyl

polar, C=O

hydroxyl

polar, hydrophilic

translation

process by which mRNA is decoded and a protein is produced

photosynthesis

process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates (glucose) 6CO2 + 6H2O + light --> C6H12O6 + 6O2

What is an enzyme and what are the functions of enzymes?

protein that speeds up chem rxns

Post-translational control refers to:

regulation of gene expression after translation

If glucose is absent, but so is lactose, the lac operon will be ________.

repressed

rRNA (structure and function)

ribosomal, makes up the structure of the ribosome

Termination

ribosome hits stop codon and falls off

Elongation of the amino acid chain

ribosome moves down mRNA

Initiation

ribosomes bind at start codon (AUG)*

Ribosomes (structure and function)

ribosomes match tRNA anticodons w/mRNA codons to add amino acids to the chain

gene

sequence of DNA that codes for a protein and thus determines a trait

how do allosteric inhibtiors affect enzyme activity?

stop enz act

Terminator (transcription)

stops transcription

How does the structure of an enzyme relate to its function?

structure determines function

What is metabolism?

sum of chem rxns in an organism

transcription

synthesis of an RNA molecule from a DNA template

tRNA (structure and function)

tRNA is used to transfer mRNA message to amino acid ribosome has to shuffle through tRNAs until it finds the right anticodon (CCG)* tRNA has the anticodon and amino acid attached tRNA anticodon matches w/mRNA codon and leaves behind its amino acid

how does temperature affect enzyme activity?

temp up, enz act up

What are epigenetic modifications?

the addition of reversible changes to histone proteins and DNA

The -10 and -35 regions of prokaryotic promoters are called consensus sequences because ________.

they have the same function in all organisms

codon

three-nucleotide sequence on messenger RNA that codes for a single amino acid

By what mechanisms do cells regulate gene expression? (be sure to understand the examples we covered in this chapter in lecture only)

transcription RNA processing translation

What is osmosis?

water moves via osmosis from an area with a high concentration of water to one of lower concentration

What is the scientific method?

A logical, systematic approach to the solution of a scientific problem 1) observation 2) question 3) hypothesis 4) prediction 5) experiment 6) analysis 7) conclusion

anticodon

A sequence of three bases of a tRNA molecule that pairs with the complementary three-nucleotide codon of an mRNA molecule during protein synthesis.

Exons

Coding segments of eukaryotic DNA.

What is the central dogma of biology?

DNA -> RNA -> Protein

DNA replication

DNA unzips into two parts and splits with the cell. each side of the DNA strand attach to matching nucleotides to create 2 exact copies.

allele

Different forms of a gene

glycolysis

Glycolysis is the process in which energy is used to break down one glucose molecule into 2 molecules of pyruvic acid (pyruvate) and the energy used forms ATP and NADH.

What are the 3 types of point mutations?

1) nonsense = stop codon reached 2) missense = amino acid changed 3) silent = amino acid doesn't change

What are the structures and functions of the major organelles of eukaryotic cells?

+ centrioles = determine the locations of the nucleus and other organelles within the cell + nucleus + endomembrane system: - nuclear envelope = separates the nucleus from the cytoplasm in eukaryotic cells - endoplasmic reticulum = synthesis, folding, modification, and transport of proteins - golgi apparatus = packaging proteins into vesicles prior to secretion - lysosomes = break down excess or worn-out cell parts - plasma membrane = protect the cell from its surroundings

What are the two major ways genes are controlled? Recall, repressible and inducible. When does this occur?

- repressible gene is one that's usually on; binding of a repressor to operator shuts off transcription - inducible gene is one that's usually off; a molecule called an inducer inactivates repressor and turns on transcription

Prokaryotic cells lack a nucleus. Therefore, the genes in prokaryotic cells are:

- transcribed and translated almost simultaneously - transcriptionally controlled because translation begins before transcription ends

What is cell theory?

1) all living things composed of 1 or more cells 2) all cells come from pre-existing cells 3) cells are basic organizational unit of life

What are the properties of water?

1) cohesion 2) adhesion 3) surface tension generated by H bonding 4) high specific heat 5) moderation of temperature 6) evaporative cooling 7) "insulation of bodies of water by floating ice", (less dense as a solid) 8) solvent of life

What are the 4 ways to attain genetic variation? Which of these are related to sexual reproduction?

1) crossing over 2) independent assortment 3) mutation 4) random fusion of gametes

What are the 2 types of frameshift mutations?

1) insertion = insert extra letter 2) deletion = delete letter

What are the mechanisms by which molecules pass through plasma membranes? Compare and contrast these mechanisms.(e.g., which mechanisms require energy? which require transport proteins? what kinds of molecules move via each mechanism?)

1) simple diffusion - from high to low conc, free 2) facilitated diffusion - from high to low conc, down conc gradient - free - cell needs to recognize meds then form protein to let meds in, carrier protein, transport protein required 3) active transport - move against conc gradient - transport protein required - not free 4) bulk transport * movement of large particles across the membrane * requires energy & transport protein a) endocytosis - entering cell + phagocytosis - engulfment of particles + pinocytosis - engulfment of liquid b) exocytosis - exiting cell

How many nucleotides are in 12 mRNA codons?

36 - each codon has 3 nucleotides

DNA composition

5 carbon sugar (deoxyribose), phosphate, nitrogenous base

Cap and tail

5' methyl guanosine cap* 3' poly-A tail* (may consist of up to 200 adenosine ribonucleotides)

Translate the mRNA sequence to an amino acid chain using the codon dictionary table from your book or the lecture PowerPoint.

5'-TRP-MET-GLY-TYR-ALA-3'

Try transcribing this DNA sequence to mRNA. 3'-ACC.TAC.CCC.ATA.CGC.ATC.TTC.CAA-5'

5'-UGG.AUG.GGG.UAU.GCG.UAG.AAG.GUU-3'

photosynthesis formula

6CO2 + 6H2O + light --> C6H12O6 + 6O2

mitosis vs meiosis

Mitosis: one division forming 2 identical cells (clones); Meiosis: two divisions forming 4 genetically different cells

Introns

Noncoding segments of nucleic acid that lie between coding sequences

citric acid cycle

completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide occurs in mitochondrial matrix, starts & ends w/oxaloacetate

What is involved in post-transcriptional control?

control of RNA splicing, shuttling, & stability

polar vs nonpolar covalent bonds

covalent bonds = between nonmetals polar = imbalanced electronegativities ex: H2O nonpolar = balanced electronegativities ex: O2

What is cytokinesis and how does it differ in plants and animals?

cytokinesis = separation of cytoplasm plants = cell plate, animals = cleavage furrow