Advanced Biology Semester 2 Final

Where does glycolysis occur?

Cytosol

Where does the Krebs cycle take place?

Mitochondrial matrix

Where does does oxidative phosphorylation take place (ETC and chemiosmosis)?

Inner membrane of the mitochondria

Which part of cellular respiration makes the most ATP, and how much does it make?

Oxidative phosphorylation (specifically chemiosmosis, not the ETC), and it makes 26-28 ATP

How many NAD and FADH2 are produced from one glucose molecule?

10 NADH, 2 FADH2

How much ATP does cellular respiration make?

30-36

How many molecules of pyruvate are made from one glucose molecule?

2

What is the function of the proton gradient?

Proteins shuttle electrons along the ETC, pumping H+ into the intermembrane space. This uses the exergonic flow of electrons from NADH and FADH2 to power chemiosmosis (uses hydrogen ions to power cellular work). Wh

What is the final electron acceptor?

Oxygen

What is the cellular respiration formula?

C6H12O6 + 6O2 → 6C02 + 6H20 + energy (ATP and heat)

What are the two ways a cell can make ATP without oxygen

Anaerobic respiration-alcohol fermentation (pyruvate into ethanol), lactic acid fermentation (pyruvate is reduced by NADH to form lactate)

What is the outcome of the krebs cycle?

2 Acetyl CoA is turned into citrate, 4 CO2 is released, 2 ATP is synthesized, electrons are transferred to 6 NADH and 2 FADH2

What materials pass through cell junctions in direct contact?

Signaling substances and other materials dissolved in the cytoplasm

Immune cells are an example of what type of cell signaling?

Direct contact-antigen presenting cells (APCs) communicate to T cells through direct contact

What is the definition of paracrine signaling?

Secretory cells release local regulators (eg. growth factors) via exocytosis to an adjacent cell

What is the definition of synaptic signaling?

Occurs in animal nervous systems, neurons secrete neurotransmitters that diffuse across the synaptic cleft-space between the nerve cell and target cell

What do animals and plants use for long distance signaling?

Hormones

Long distance signaling-plants

Plants release hormones that travel in the plant vascular tissue (xylem and phloem) or through the air to reach target tissues

Long distance signaling-animals

Endocrine signaling-specialized cells release hormones into the circulatory system where they reach target cells

Insulin is an example of what type of signaling?

Insulin (a hormone) is long-distance signaling because insulin is released by the pancreas into the bloodstream (circulatory system) where it circulates through the body and binds to target cells

What type of communication involves a cell secreting a substance to an adjacent target cell?

Paracrine signaling

What are second messengers and what do they do?

Small, non-protein molecules and ions that help relay the message and amplify the cellular response (think cAMP)

What is homeostasis and why is it important?

The state of relatively stable internal conditions. It is important for organisms to maintain balance by detecting and responding to stimuli. The body maintains homeostasis through feedback loops.

What is positive feedback?

Type of feedback that increases the effect of the stimulus

What is negative feedback?

Reduces the effect of the stimulus (think regulation)

Fruit ripening, childbirth, and blood clotting are all examples of what type of feedback?

Positive feedback

Sweat, blood sugar, and breathing rate are all examples of what type of feedback?

Negative feedback

What are the three potential outcomes of a signal transduction pathway?

1. Protein can alter membrane permeability. 2. Enzyme that will change a metabolic process. 3. Protein that turns genes on or off

What will happen to a signal transduction pathway is a receptor is mutated?

Causes a change in the transduction of the signal

What enzymes regulate phosphorylation during a signal transduction pathway?

Protein kinase and protein phosphatase

What does protein kinase do?

Phosphorylates a protein to relay a signal inside the cell

What does protein phosphatase do?

Dephosphorylates protein, shutting off pathways

What are cyclin-dependent kinases?

Enzymes that have a specific regulatory effect, active CDK complexes phosphorylate target proteins, which help regulate events in the cell cycle, active only when its specific cyclin is present

If the percentage of adenine is 30%, what is the percentage of guanine, thymine, and cytosine?

Thymine-30%, guanine-20%, cytosine-20%

What are the base pairing rules for DNA and RNA, including the number of bonds?

A-T (U for RNA), 2 hydrogen bonds, C-G, 3 hydrogen bonds

Why are telomeres so important?

They form a cap at the end of DNA to help postpone erosion

What is the function of helicase?

unwinds the DNA strands at each replication fork

What is the function of DNA polymerase III?

Attaches to primer on the parental strand, adding nucleotides to the new strand

What direction does DNAP III move?

3’ to 5’

What direction does DNAP III add nucleotides?

5’ to 3’

What is the function of DNAP I?

Removes RNA primers and fills in gaps with single-stranded DNA

Topoisomerase

helps prevent strain ahead of the replication fork by relaxing supercoiling

Primase

Initiates replication by adding short segments of RNA called primers to the parental strand, foundation for DNA synthesis

What is the function of RNA polymerase?

Transcribe DNA into RNA during transcription

How can epigenetics modify DNA?

Chromatin structure-histone acetylation and DNA methylation-loosens or condenses chromatin, can be heritable to future generations. Transcription initiation-Transcription factors bind to control elements due to chromatin modifications making DNA more accessible, gene expression can be increased or decreased by binding of activators or repressors to control elements, alternative splicing of pre-mRNA

What does it mean that DNA replication is semi-conservative?

The two parental strands copy itself, after one round of replication the daughter molecules will each have one parental and one new strand

How is genetic coding universal and why is this important?

Nearly all organisms share the same code (where three nucleotide sequences (codons) specify the same amino acids. This is important because it provides evidence of common ancestry.

What are SSBPS and what do they do?

Single strand binding proteins, they bind to the DNA to keep it from re-binding with itself

How does transcription initiate in eukaryotes?

promoter region is called the TATA box, RNA polymerase can bind directly to the promoter

How does transcription initiate in prokaryotes?

RNA polymerase can bind directly to promoter

What are the three necessary pre-mRNA modifications that have to occur in eukaryotes before translation?

5’ cap, Poly-A tail, RNA splicing

What is the 5’ cap?

pre-mRNA modification, 5’ end of the pre-mRNA receives a modified guanine nucleotide “cap”

What is the poly-A tail?

pre-mRNA modification, the 3’ end of the pre-mRNA receives 50-250 adenine nucleotides

What is RNA splicing?

sections of the pre-mRNA, called introns, are removed and then exons are joined together

What are introns?

Intervening sequence, do not code for amino acids

What are exons?

Expressed sections, code for amino acids

What is the role of DNA in cells?

to store and transmit genetic information, acting as the cell's blueprint for development and function

What is the backbone of DNA?

sugar-phosphate, made up of deoxyribose molecules connected to each other using phosphates

What is a purine?

6 and 5 membered rings nitrogenous bases (C and G)

What is a pyrimidine?

6 member ring nucleotide bases, C, T, U

Why is an RNA primer necessary for DNA replication?

The enzymes that synthesize DNA can only attach new DNA nucleotides to an existing strand of nucleotides

Why is the lagging strand not synthesized continuously?

DNA is always synthesized 5’ to 3’, and the lagging strand moves towards helicase

What are the three stages of translation?

Initiation, elongation, termination

How is translation initiated?

A small ribosomal subunit binds to the mRNA and a charged tRNA binds to the start codon (AUG) on the mRNA, tRNA carries methionine, then the large subunit binds

What are the three steps of elongation during translation?

Codon recognition, peptide bond formation, translocation

Elongation in translation

tRNA comes into the A site, mRNA is moved through the ribosome and its codons are read, each mRNA codon codes for a specific amino acid

Codon recognition

the appropriate anticodon of the next tRNA goes to the A siteP

Peptide bond formation

peptide bonds are formed that transfer the polypeptide to the A site

Translocation

the tRNA in the A site moves to the P site, the tRNA in the P site goes to the E site, the A site is open for the next tRNA

Termination of translation

A stop codon in the mRNA reaches the A site of the ribosome, the stop codon signals for a release factor, hydrolyzes the bond that holds the polypeptide to the P site, polypeptide releases, all translational units disassemble

What are the three types of RNA?

tRNA (transfer RNA), mRNA (messenger RNA), rRNA (ribosomal RNA)

tRNA

Transfer RNA, important for translation because they each carry a specific amino acid, can attach to mRNA via their anticodon and allow information to be translated into a peptide sequence

mRNA

Messenger RNA, synthesized during transcription using a DNA template, carries information from the DNA (at the nucleus) to the ribosomes in the cytoplasm

rRNA

Ribosomal RNA, helps form ribosomes and link amino acids together

Alternative splicing

a cellular process in which exons from the same gene are joined in different combinations, leading to different, but related, mRNA transcripts

Operon

a group of genes that can be turned on or off

What are the three parts of an operon?

Promoter, operator, genes

What does the LAC operon control?

Synthesis of lactase, an enzyme that digests lactose (milk sugar)

Is the LAC operon inducible or repressible?

Inducible, a LAC repressor is bound to the operator (allosterically active)

What is the inducer for the lac repressor?

Allolactose

What does the presence of allolactose (inducer) mean?

Allolactose will bind to the lac repressor and turn the lac repressor off, allowing the genes to be transcribed

A site

Amino acid site (arrival site) holds the next tRNA carrying an amino acid

P site

polypeptide site, holds the tRNA carrying the growing polypeptide chain

E site

exit site

What are three similarities between mitosis and meiosis?

1. Starts with one diploid parent cell. 2. Cells undergo DNA replication. 3. Same basic steps

What are aspects of mitosis that don’t apply to meiosis?

Produces two diploid daughter cells, daughter cells are genetically identical, involves one cell division, creates all body cells

What are aspects of meiosis that don’t apply to mitosis?

Creates only gametes, involves two cell divisions, produces four haploid daughter cells, daughter cells are genetically different

What is crossing over and when does it occur?

DNA is exchanged between the homologous pairs, occurs during prophase I

If a cell’s diploid number is 8, what is its haploid number?

4

What two types of complex inheritance is blood type?

Codominance and multiple alleles

How is map distance calculated?

One map unit is equal to one percent recombination frequency

What are linked genes?

Genes located near each other on the same chromosome that tend to be inherited together

If X-squared is greater than the critical value, the null hypothesis is:

rejected, there is a statistically significant difference between observed and expected values

If X-squared is less than the critical value, the null hypothesis is:

Fail to reject it, there is not a statistically significant difference between observed and expected values

What is the outcome of meiosis?

Four haploid, genetically different daughter cells

X-linked gene

gene located on the X chromosome

What is the order of the cell cycle, including interphase?

G1-S-G2 (interphase)-Prophase, prometaphase, metaphase, anaphase, telophase (mitosis), cytokinesis

Homologous chromosomes

two chromosomes (one from mom and one from dad) that are the same length, have the same centromere position, and carry genes controlling the same characteristics