HA&P: Chapter 3 - Part 3

What is the series of changes a cell goes through from the time it is formed until it reproduces?

Cell cycle

What are the two major periods of the cell cycle in the outer ring?

Interphase & Cell division (mitotic phase)

This is the period from cell formation to cell division and the cell grows and carries on its usual activities?

Interphase

What is the interphase divided into?

G1 (gaps), S (synthetic), G2

Which subphase is where the cell is metabolically active, synthesizing proteins rapidly and growing vigorously, is the most variable phase in terms of length, and it lasts several minutes to hours, and as it ends the centrioles start to replicate in preparation for cell division?

G1 (gap 1 subphase)

What is it called when cells permanently stop dividing?

G0 phase

What subphase of interphase, is where the DNA is replicated, to ensure that the two future cells being created will receive identical copies of the genetic material and new histones are made and assembled into chromatin?

S phase

What subphase in the interphase, is the final phase of interphase, the enzymes and other proteins needed for division are synthesized and moved to their proper sites, and at the end, the centrioles replication is complete?

G2 (gap 2 subphase)

What are the four events of Replication?

1. Uncoiling: enzymes unwind the DNA molecule, forming a replication bubble

2. Separation: the two DNA strands separate as the hydrogen bonds between base pairs are broken, to the point which it unzips being the replication fork

3. Assembly: with the old strands acting as templates, the enzymes DNA polymerase positions complementary free nucleotides along the template strands, forming two new strands, there will be two new strands of leading and lagging strands, which are synthesized in opposite directions and with each new molecule it can be called semiconservative replication

4. Restoration: ligase enzymes splice short segments of DNA together, restoring the double helix structure

What two events are distinct in the M (mitotic) phase?

Mitosis & Cytokinesis

What part of the M(mitotic)phase is the division of the nucleus, is the series of events that parcels out the replicated DNA of the parent cell to two daughter cells, and has four phases of Prophase, Metaphase, Anaphase, & Telophase?

Mitosis

What part of the m(mitotic)phase is the division of the cytoplasm, that begins during late anaphase and is completed after mitosis ends?

Cytokinesis

A contractile ring made of actin filaments draws the plasma membrane inward to form this over the center of the cell, which it deepens until it pinches the cytoplasmic mass into two parts, yielding two daughter cells?

Cleavage furrow

What is the G1 checkpoint known as which is another key point at which a stop signals can halt further growth?

Restriction point

What two groups of proteins are crucial to a cell’s ability to finish the S phase and it enters mitosis?

Cyclins and Cyclin dependent kinases

What are the four nucleotide bases that are the “letters” of the genetic alphabet and the information of DNA is found in the sequence of these bases?

A, G, T, and C

What is it called with each sequence of three bases, like the triplet AAA calls for the amino acid phenylalanine?

Triplet

What is the ration between DNA bases in the gene and amino acids in the polypeptide?

3:1

Coding regions are called a.__________ that are separated from each other by long intervening sequences called b.____________

a. Exons

b. Introns

What form of RNA is relatively long nucleotide strands resembling “half-DNA” molecules and it carries the coded information to the cytoplasm where protein synthesis occurs?

Messenger RNA (mRNA)

What form of RNA forms the ribosomes, that consist of two subunits that combine to form functional ribosomes which are the sites of protein synthesis?

Ribosomal RNA (rRNA)

What form of RNA are small, roughly L-shaped molecules that ferry amino acids to the ribosomes and they decode mRNA’s message for amino acid sequence in the polypeptide to be built?

Transfer RNA (tRNA)

What are the two major steps in Polypeptide Synthesis?

1. Transcription, in which DNA’s information is encoded in mRNA

2. Translation, in which the information carried by mRNA is decoded and used to assemble polypeptides

What phase of the prophase is where the chromatin coils and condenses, forming barlike chromosomes, each duplicated chromosome consists of two identical threads, called chromatids, held together at the centromere, the centrosomes act as focal points for growth of a microtubule assembly, and the asters extend from the centrosome matrix?

Early Prophase

What phase of the prophase, is where the nuclear envelope breaks up, allowing the spindle to interact with the chromosomes, some growing spindles microtubules attach to kinetochores, and the remaining spindle microtubules slide past each other?

Late prophase

What phase in the mitosis is where the two centrosomes are at opposite poles of the cell, the chromosomes cluster at the midline of the cell, and at the end, the enzymes that will act to separate the chromatids from each other are triggered?

Metaphase

What phase in the mitosis, is where it begins as the centrosomes of the chromosomes split, each chromatid now becomes a chromosome, the kinetochore microtubules shorten, and the nonkinetochore microtubules slide past each other?

Anaphase

What phase in the mitosis, is the final phase, begins as soon as chromosomal movement stops, the identical sets of chromosomes at the opposite poles of the cell begin to uncoil, a new nuclear envelope forms around each chromatin mass, and the spindle breaks down and disappears?

Telophase

What begins during late anaphase and continues through and beyond telophase?

Cytokinesis

What transfers information from a DNA base sequence to the complementary base sequence of an mRNA molecule and it cannot begin until gene-activating chemicals called transcription factors stimulate histones at the gene transcription site to loosen?

Transcription

What does the transcription factors bind to, that is a special DNA sequence that contains the start point of the gene to be transcribed and it specifies which DNA strand is going to serve as a template strand?

Promoter

What will initiate the transcription when the uncoiled DNA strand not used as a template is the coding strand that has the same sequence as the mRNA to be built?

RNA polymerase

What are the three phases of transcription?

Initiation, Elongation, Termination

What phase of transcription, is where the RNA polymerase bind to the promoter, pries apart the two DNA strands, and initiates mRNA synthesis at the start point within the promoter region?

Initiation

What phase of transcription, is where the RNA polymerase moves along the template strand, joining together RNA nucleotides complementary to the DNA and it elongates the mRNA transcript one nucleotide at a time, unwinding the DNA double helix in front and rewinding it behind?

Elongation

What phase of transcription is where the mRNA synthesis ends when the polymerase reaches a special nucleotide sequence called a termination signal and RNA polymerase and the complete mRNA transcript are released?

Termination

What are the rules by which the base sequence of a gene is translated into an amino acid sequence?

Genetic code

For each triplet, or three-base sequence on DNA the corresponding three-base sequence on mRNA is?

Codon

Since there are 64 codons, what can they be called, that call for termination of polypeptide synthesis?

“Stop signs”

What RNA is suited to its dual function of binding to both an amino acid and an mRNA codon and there is a amino acid that is bound to the end?

tRNA

This is at the other end, it is a three-base sequence, which binds to the mRNA codon calling for the amino acid carried by that tRNA?

Anticodon

In the stage of initiation in Translation, there is this small ribosomal subunit that bind this, and then to the “new” mRNA to be decoded?

Initiator tRNA

What happens at the end of the initiation event in translation?

The mRNA is positioned in the groove between the ribosomal subunits, the initiator tRNA is sitting in the P site, and the A site is vacant, ready for the next aminoacyl tRNA to deliver its cargo

What happens in the elongation event of Translation?

The ribosome moves along the mRNA in one direction and one amino acid at a time is added to the growing polypeptide

What are the three-step cycles of elongation?

1. Codon recognition: the incoming aminoacyl-tRNA binds to a complementary codon in the A site of a ribosome

2. Peptide bond formation: an enzymatic component in the large ribosomal subunit catalyzes peptide bond formation between the amino acid of the tRNA in the P site and that of the tRNA in the A site

3. Translocation: the ribosome translocates, or moves shifting its position one codon along the mRNA

What happens in the Termination event in Translation?

The mRNA strand is read until its last codon, the stop codon enters the A site which it is the period at the end of the mRNA sentence, as it tells the ribosome that translation of that mRNA is finished

What is present in a protein that is being synthesized, its associated ribosome attaches to the membrane of the rough ER?

ER signal sequence

These are small RNAs that can interfere with and suppress mRNAs made by certain axons?

MicroRNAs

These are like miRNA but they originate outside the cell?

Small interfering RNAs

What process sweeps us bits of the cytoplasm and unneeded organelles into double-membrane vesicles called autophagosomes and its functions are that it allows cells to dispose of clumps needed proteins, allows cells to cannibalize parts in order to survive, and helps restructure cells during development?

Autophagy (“self-eating”)

This handles individual proteins that are misfolded, damaged, or unneeded and must be disposed of?

Ubiquitin-proteasome pathway

What proteins are doomed proteins that are marked for destruction and are attached to them?

Ubiquitins

Ubiquitins are hydrolyzed to these small peptides, that are giant “waste disposal” complexes composed of protein-digesting enzymes?

Proteasomes

These get rid the body of cells that are programmed to have a limited life span?

Apoptosis, or Programmed cell death

What is the development of specific and distinctive features in cells called?

Cell differentiation

What is accelerated growth, and if a person is anemic there bone marrow goes through this?

Hyperplasia

This is a decrease in size of an organ or body tissue, that can result from loss of normal stimulation or from disease like muscular dystrophy?

Atrophy