CH 9
Cell Signaling
Cell Signaling
What enzyme adds a phosphate group to another molecule
Kinase
The three main types of cytoskeletal filaments
Microfilaments, Microtubules, and Intermediate filaments
DNA polymerase adds a new nucleotide to
DNA polymerases can only add nucleotides to the 3' end of an existing DNA strand.
What are the phases of Interphase
The three main phases of interphase are G1 (Gap 1), S (Synthesis), and G2 (Gap 2). GO is also a phase and is where cells go when they are not actively dividing
Genotype vs Phenotype
Genotype is an organism's complete genetic makeup, while phenotype is the set of its observable characteristics
Explain Paracrine signaling
Paracrine signaling is a type of cell communication where a cell releases a chemical messenger that affects only the nearby target cells
What is the difference between Cadherins and Integrins
Cadherins: Cell - Cell
Integrins: Cell - Extracellualr Matrix
Helicase vs Topoisomerase
Helicase : unwinds the dna
Topoisomerase : relieves the stress of unwinding
What occurs during Metaphase
Chromosomes line up on the metaphase plate in a single file line
MIDDLE = METAPHASE
What is a nonsense mutation. Is it "better" for this to occur early or late
codon changed to a stop codon (UAA, UGA, or UAG), causing premature termination of the protein
nonsense mutation to happen late in a gene rather than early, as a late mutation can lead to a less severe phenotype
What is the difference between a first messenger and a second messenger (with examples)
A first messenger (or ligand) is an extracellular signaling molecule that binds to a receptor on the cell surface
A second messenger is an intracellular molecule, like cAMP, that transmits the signal inside the cell to produce a response.
What are the five types of cell junctions
Adherens Junctions
Desmosomes
Hemidesmosomes
Tight Junctions
Gap Junctions
Where does DNA polymerase start on the DNA strand
RNA primer
What is Cytokinesis? What is the difference between cytokinesis in plants and animals
Cytokinesis is the final step of cell division where a cell's cytoplasm is divided to form two separate daughter cells.
Animal cells use a cleavage furrow that pinches inward, while plant cells form a cell plate that grows outward to form a new cell wall.
Insertion : add extra base pairs
Deletion : a base pair is removed
Substitution : wrong base is matched
What does cAMP activate?
Protein Kinase A
What cell junctions are are used for anchoring and what is the major component
Adherens Junctions : Cadherins
Desmosome : Cadherins
Hemidesmosome : Integrin
Where are Okazaki fragments found and what enzyme binds them together
Okazaki fragments are found in the lagging strand. \
DNA ligase forms a bond joining the two DNA fragments
DNA damage checkpoint: before entering S phase. Is DMA damaged?
DNA replication checkpoint: at the end of G2. Is all DNA replicated?
Spindle assembly checkpoint : before anaphase. Are all chromosomes attached to the spindle?
What is Translocation
A translocation is a type of chromosome mutation where a segment from one chromosome breaks off and attaches to another chromosome.
Explain GPCR signal transduction pathway from start to finish
A ligand binds to receptor associated with G protein, causing it to release GDP and bind to GTP, which then dissociates into two subunits (beta and gamma) that activate downstream effector proteins. These effectors can be enzymes or ion channels that produce second messengers like cAMP or activate further signaling cascades, ultimately leading to a cellular response.
What is the difference between Adherens Junctions and Desmosomes
Adherens junctions link to microfilaments and are involved in cell shape and movement, while desmosomes link to intermediate filaments and are critical for providing mechanical strength
One of the roles of DNA polymerase is proofreading. What does it proofread? what happens when there is an error?
DNA polymerase proofreads the newly synthesized DNA strand for incorrect base pairs that may have been incorporated during replication. CHARGRAFF's Ru;es A-T C-G
If an error is detected, the polymerase backtracks, removes the wrong nucleotide, and then insert the correct one before continuing.
Explain what occurs in EACH step of Mitosis.
Prophase : Chromosomes condense
Prometaphase : Nuclear envelope breaks apart
Metaphase : Chromosomes line up on the metaphase plate, specifically here in a single file straight line.
Anaphase : Chromosomes separate, specifically here sister chromatids separate
Telophase : Chromosomes move further apart; Nuclear envelopes reform; and Chromosomes decondense
Cytokinesis : Physical cell division; Cytoplasm, and organelles are divided into 2 cells.
What is silent mutation?
A silent mutation is a change in DNA that does not alter the amino acid sequence of a protein