bio test im cooked for

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cell communication (v)

Method by which cells communicate with each other, via chemical signal

dephosphorylation (v)

process to remove phosphates

intracellular receptor (v)

receptor molecule located within the cell

ligand (v)

signal molecule intended for binding

phosphatase (v)

enzymes that catalyze the removal of phosphates

photodiester bond (v)

bond between the 5’ phosphate group of one nucleotide and the 3’ hydroxyl group of the next nucleotide; Bond that builds a DNA strand

purine (v)

nitrogenous base in DNA made up of two linked rings; Includes adenine & guanine

pyrimidine (v)

nitrogenous base in DNA made up of a single ring; includes cytosine & thymine

signal transduction pathway (v)

process of going from signal reception to transduction of the signal to a cellular response

transmembrane receptor (v)

receptor molecule embedded in cell membrane

2 reasons why cell signaling is necessary for living organisms (list)

10) cell signaling is essential to a living things’ ability to grow & develop 2) cell signaling is essential to a living things’ ability to reproduce

describe cell communication in prokaryotes, like bacteria (mc)

used to monitor the number of bacteria cells present in a particular environment – if a few cells, encouraged; can modify or slow the growth of the bacteria

describe cell communication in unicellular eukaryotes, like yeast (mc)

used to identify the proper cell for mating – allowing an alpha strain to find an a strain and v.v.

describe cell communication in multicellular eukaryotes, like plants (mc)

used when plants release chemicals used for regulating plant growth in the roots & stems – cell division that elongates these structures. This chemical can regulate another plant species’ growth as well.

describe cell communication in multicellular eukaryotes, like animals (mc)

used when hormones in animals begin at one organ & communicate an action to another organ or tissue – starts in the brain & can increase cell division in the bones and muscles to make an animal taller / bigger

mechanism of G protein coupled receptor (mc)

transmembrane protein that binds to a protein complex called G portion, consisting of alpha, beta, and gamma subunits

mechanism of tyrosine kynase receptor (mc)

transmembrane protein that joins with another RTK molecule

mechanism of ligand-gated ion channel (mc)

simpler transmembrane protein receptor that looks like a channel or pore embedded in a membrane – but with a receptor

mechanism of intracellular receptor (mc)

receptors found inside a cell, sometimes even in the nucleus

inactive state of g-protein coupled receptor (mc)

G protein is bound to GDP, similar to ADP, and separate from receptor protein

inactive state of ligand-gated ion channel (mc)

empty receptor site & closed channel, with no molecules moving across the membrane

inactive state of tyrosine kynase receptor (mc)

when RTK is by itself

steps of g-coupled protein reception (order)

1) ligand binds to receptor, causing the receptor to change shape & the G protein to bind to the GPCR.

2) GTP molecule binds to the G protein, replacing GDP & activating the G protein.

3) G protein dissociates; separated move thru the membrane to bind to other enzymes. The enzymes activate or switch to an active comformation.

4) enzymes catalyze rxns that transmit the signal into the cell. GDP replaces GTP in the G protein, causing the subunits to bind back together.

5) the G protein returns to an inactive state.

steps of tyrosine kynase reception (order)

1) two ligands come and bind to two separate RTK molecules.

2) the receptors bind together to form a dimer.

3) dimer is activated by phosphorylation involving six ATP molecules at the tyrosine amino acid sites.

4) six dimer phosphate sites each bind to a relay protein, activating it with phosphate, creating a structural change in the relay proteins.

5) multiple activated relay proteins trigger signal transduction pathways, causing a message to be relayed to the cell. Cell creates a response.

describe the most common cellular response created by an intracellular receptor (mc/tf)

to operate a transcription factor that permits DNA to be transcribed into RNA; Usually for the purpose of ‘turning on’ a particular gene so that it can be used to make a particular protein

two reasons why multi-step signal transduction is advantageous (sa)

1) controlled & efficient relay of info into the cell

2) enables the signal to be passed deeply into the cell because each protein is activating multiple proteins after it

explain the factor that makes second messengers unique in signal transduction (sa)

they are usually small, non-protein molecules that can diffuse quickly throughout the cell. Once triggered, they can create a variety of cellular responses.

describe the mechanism of cAMP (mc)

they are usually small, non-protein molecules that can diffuse quickly throughout the cell. Once triggered, they can create a variety of cellular responses.

describe the mechanism of Ca2+ (mc)

normally, Ca2+ are very low inside the cell; When signal is received, channels open to enable Ca2+ to flood into cell; When cytoplasmic Ca2+ rapidly increases, various responses created

describe & explain how adrenaline as a common signal with different receptors is effective (sa)

Heart cells with beta receptors; when adrenaline binds there, it causes the heart muscle to contract more strongly & frequently. Liver cells have alpha receptors; when adrenaline binds there, it causes the liver cells to break down the glycogen stored within and releases its glucose monomers into the bloodstream When the same ligand has different receptors, different cell responses are created. These help to create specific responses needed by each cell. Drugs in a class known as beta-blockers work by binding to the same receptor molecules that accept the ligand epinephrine. They cause the heart to beat slower and with less force, leading to a decrease in blood pressure. In terms of cell signaling, explain how the beta blockers accomplish this. Because heart calls have special adrenaline receptors called beta-adrenergic. When epinephrine binds to this receptor, it is activated & tells the heart to contract more strongly & frequently. Since beta blockers bind to the same receptor molecule at the beta receptor, preventing the ligand, epinephrine, from binding, the receptor cannot be activated by the ligand.

DNA’s nucelotides - nitrogenous base (mc)

1 of 4 Adenine, Thymine, Cytosine, Guanine – sequence is code for storing info needed to run an organism

DNA’s Nucleotides - Sugar (mc)

1 deoxyribose molecule

DNA’s Nucleotides - Phosphate (mc)

1 phosphate group

explain two advantages of redundancy in DNA (sa)

1) DNA must be copied repeatedly & genetic info is able to maintain stability over long periods of time

2) Two strands can briefly separate so that code can be easily copied & sent to other parts of the cell

compare & contrast phosphatases & kinases (mc/tf)

both proteins; phosphatase phosphate action - Catalyze the removal of phosphates; kinase phosphate action - transfer phosphate group from one molecule to another

tf

Phosphorylation cascades can sometimes activate thousands of proteins.

tf

If phosphorylation activates a molecule, dephosphorylation deactivates a molecule.

overview of interphase (mc)

Most of the cell’s life (90%) ; Carry out normal functions (respiration) & specific functions (contracting muscle cell), while growing & preparing the cell to divide ; G1 – Normal cell functions + Increase size, proteins, organelles, S – Complete copy of genetic material is made ; G2 – Prepares to divide

overview of mitotic (mc)

Very little of cell’s life (10%) ; Division of all aspects of the cell – materials, chromosomes – into 2 cells genetically identical to original cell ; Mitosis – Duplicated genetic material separated so each cell has full genome ; Cytokinesis – Division of cytoplasm into 2 separate cells

Adenine & Thymine (mc)

2 bonds

Cytosine & Guanine (mc)

3 bonds

3’ (potential carbon atoms) (mc)

Hydroxyl group end of deoxyribose sugar

5’ (potential carbon atoms) (mc)

Phosphate group end of deoxyribose sugar

Describe the bonding details of DNA (mc)

Complementary strands - Run in opposite directions, called being antiparallel ; How bonded - Photodiester bond