Chapter 3 Flashcards by Sarah Mortimer

What is in the cytoplasm?

-cytosol
-organelles
-cytoskeleton

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What is another name for ECF?

Interstitial fluid

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What are the concentrations inside and outside of the cell?

-Potassium (K+) high in concentration inside of the cell
-Sodium (Na+) low in concentration outside of cell

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How are the phospholipids in the plasma membrane oriented?

-head is polar
-tail is nonpolar
-tails point toward one another

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What is on the outer part of the plasma membrane?

Peripheral proteins

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What can’t get through the plasma membrane?

charged particles

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What are the hexagons associated with the plasma membrane?

-Sugar
-Identifier
-Might be bound to proteins/phospholipids

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What are glycoproteins?

-Protein with carbohydrate attached

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Where is cholesterol in the plasma membrane and what is its purpose?

-Embedded in plasma membrane
-Makes membrane more flexible
-Necessary for healthy cells because of flexibility/fluidity.

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What is a membrane protein channel’s structure/function?

Tunnel through plasma membrane

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What is a membrane protein carrier’s structure/function?

-Opens things up
-More intentional
-Binds and transports substances in or out of the cell

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What is a membrane protein receptor’s structure/function?

-outside of cell
-Molecule binds onto them
-triggers change in membrane protein or cell

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What is a membrane protein enzyme’s structure/function?

-Will always be a protein
-Catalyzes chemical reactions inside cell

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What is a membrane protein structural support’s structure/function?

-Membrane proteins bind other proteins in the ECF and/or the cytosol, supporting cell

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What is a membrane protein linking adjacent cell’s structure/function?

-Link adjacent cells in a tissue together
-like velcro

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How is diffusion characterized?

-will always be passive
-needs concentration gradient
-SOLUTE will move until equilibrium is reached

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What is simple diffusion?

-Type of diffusion that does not need protein to go through plasma membrane
-nonpolar; can move through membrane easily
-Hydrophilic (steroid hormones, oxygen, CO2)

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What is facilitated diffusion?

-Connects ICF to ECF
-Needs channel to go through (Na+ and K+ for example)
-Polar

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What happens with facilitated diffusion of polar and ionic compounds?

Molecule binds to carrier and carrier changes shape and opens carrier to inside of cell

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What is osmosis?

-WATER moves from an area of lower solute concentration to an area of higher solute concentration area until equilibrium is reached
-requires semi-permeable membrane
-passive

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What is tonicity?

The sum of all dissolved substances (a way to compare osmotic pressure gradients between 2 solutions)

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What does isotonic mean?

-both fluids have approximately the same concentration
-no net movement of water
-no volume changes

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What does hypertonic mean?

-higher solute concentration outside cell
-water leaves cell
-cell shrivels
-crenation (shrunken cell that looks spiny because cytoskeleton is poking out)

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What does hypotonic mean?

-Higher solute concentration inside cell
-water enters cell
-swells cell and cell may burst

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What is the active transport NA+ K+ Pump?

K+ moves into cell Na+ moves out of cell Moves Na out/K in against concentration gradients MAINTAINS gradients

How is the transmembrane potential characterized?

inside of cell negative compared to outside at rest plasma membrane and active transport help maintain potential (electrical gradient)

What is endocytosis?

-use vesicles to move larger things -vesicles are membrane-bound containers formed from plasma membrane -bringing outside to inside using vesicle

What is phagocytosis?

-type of endocytosis that brings very large particles into cell -usually bacteria or damaged or dead cells of parts of cell

How does phagocytosis occur?

-Bacteria binds to receptor in plasma membrane -Pseudopods reach and surround particles -Phagosome (vesicle) fuses with lysosome and it is digested

What is pinocytosis?

-type of endocytosis -takes small samples of ECF -way of sampling

How does pinocytosis occur?

-forms tiny vesicle -transport vesicle loses protein coat and fuses with endosome -either returns to plasma membrane, sent to lysosome, or may exit out of opposite side of cell

What is exocytosis?

-things inside of cell released to outside -cell forms vesicles -fuses with plasma membrane and is released to outside

Which organelles are membrane-bound?

mitochondria, peroxisomes, ER, golgi apparatus, lysosomes

Which organelles are not membrane-bound?

ribosomes and centrosomes

What do mitochondria do?

-makes ATP (consumes O2, CO2 waste) -Has its own DNA

What do peroxisomes do?

Use hydrogen peroxide (H2O2) to destroy toxins and fatty acids in the body -synthesizes some phospholipids

What are ribosomes structure/function?

-Physically made up of RNA -Protein synthesis

Where are ribosomes fixed and free?

Free in cytosol and bound in ER

What is the endoplasmic reticulum?

-network membranes involved in synthesis mainly for secretion (leaving cell)

What is the structure/function of the Rough ER?

-studded with ribosomes -involved in protein processing

What is the structure/function of the Smooth ER?

-no ribosomes -lipid synthesis (such as steroids and cholesterol)

What is the function of the Golgi Apparatus?

-involved in packaging products from the ER into vesicles for secretion (exocytosis) --Also makes lysosomes

What are lysosomes?

-vesicle-looking with digestive enzymes inside (powerful) -3 functions include cleaning up the inside of the cell, getting rid of residue, and apaptosis (cell destroying itself)

What conditions (1) cause a lysosome to be activated?

-A primary lysosome fuses w/ the membrane of another organelle, such as mitochondrion

What conditions (2) cause a lysosome to be activated?

-A primary lysosome fuses w/ an endosome containing fluid or solid materials from outside the cell

What conditions (3) cause a lysosome to be activated?

-The lysosomal membrane breaks down during autolysis following injury to, or death of the cell

What is in the cytoskeleton?

-actin (microfilaments) -intermediate filaments -microtubules

What are microtubule structures?

-Centrioles -cilia -flagella

What do centrioles do?

-inside the centrosome -involved in mitosis

What do cilia do and where are they?

-involved in sweeping across cell surface -long -surface of cell (in airways, in reproductive)

What are flagella and where are they?

-allow cell to "swim" -tail that whips to propel cell forward -only in sperm

What is the structure/function of microvilli?

-have microfilaments at core -extensions of plasma membrane -serve to increase surface area for absorption

What is the nucleus?

-command center of cell -contains DNA -Nuclear envelope with pores -Nucleolus responsible for rRNA and making ribosomes

What is the function of DNA?

protein synthesis

What is chromatin?

-one extremely long DNA molecule -Nucleotides strung together form proteins

What is the structure/function of a nucleosome?

-strand of DNA coiled around group of histone proteins -like beads on string -supercoils into visible chromosome for cellular division

What is transcription and where does it happen?

-happens in nucleus -DNA to mRNA

What is translation and where does it happen?

-in cytoplasm on ribosomes -Ribosome reads code from mRNA -Assembles amino acids into polypeptide chain

What is processing and where does it happen?

-By RER & Golgi Apparatus; produce protein -A gene codes for a specific protein

What happens in the initiation stage of transcription?

-transcription factors bind to promotor -RNA polymerase (does copying) unravels DNA and binds to promoter

What happens in the elongation stage of transcription?

-Building RNA in complementary nucleotides -3 letter code on DNA is triplet -3 letter code on mRNA is codon -3 letter code on tRNA is anticodon

What happens in the termination stage of transcription?

-end of gene is reached -mRNA transcript is released

What is the first step of translation?

-Initiator RNA binds the mRNA start codon in the ribosome

What is at the other end of tRNA?

anticodon; complementary to codon on mRNA

What does the anticodon bring in?

-amino acid

What is the A site?

-site that is accepting site for new tRNA's to bring amino acids

What is the P site?

-for building peptide bonds

What is the E site

-exiting site

What happens in processing?

-Protein is folded and modified into final protein, most of which occurs in the cytosol or rough ER.

A long, thin strand of DNA and its associated proteins is called

chromatin

Human cells that lack centrioles cannot

divide

Where does protein synthesis occur?

ribosomes

Which of the following functions is not associated with the peroxisomes? -digesting worn-out organelles -breaking down fatty acids -synthesizing certain phospholipids -oxidizing toxic substances

digesting worn-out organelles

Which organelle has a second inner membrane that has folds called cristae, and a matrix?

mitochondrion

Which of the following organelles is not part of the endomembrane system? -lysosomes -peroxisomes -golgi apparatus -Smooth ER

peroxisomes

Which cellular extensions can increase the surface area of the plasme membrane up to 40%?

microvilli

What organelle modifies polypeptides so they can fold into fully functional proteins?

Rough ER

Which of the following functions does not relate to the smooth ER? -Protein synthesis -detoxification reactions -calcium ion storage -lipid synthesis

protein synthesis

Which of the following functions is not associated with intermediate filaments within the cell? -associating with motor proteins to move vesicles and organelles throughout the cell -forming a network under the membrane around the nucleus to support its shape and size -forming a network within the cytoplasm that gives the cell mechanical strength

associating with motor proteins to move vesicles and organelles throughout the cell (function of microtubules)

Within the nucleus, where does ribosome assembly occur?

Nucleolus

______ are tightly coiled and condensed barlike structures that separate during anaphase

Chromosomes

The Na+/K+ pump transports _____ out of the cell for every _____ moved into the cell

three sodium ions; two potassium ions

Which of the following functions is associated with many plasma membrane proteins? -promotes fluidity of the membrane -oxygen transport -molecular transport through the membrane -forms a lipid bilayer

molecular transport through the membrane

Neurotransmitters are released from secretory vesicles in neurons by a process called

exocytosis

_____ stabilizes the structure of the plasma membrane when the temperature changes

Cholesterol

Sodium ions move through the plasma membrane through a carrier protein using no energy in ____

facilitated diffusion

Ingesting cellular debris occurs in a process called

phagocytosis

Carbon dioxide is a small molecule that moves through the phospholipid bilayer with its concentration gradient by ______

simple diffusion

Two types of active transport vesicles are

endocytosis and exocytosis

During which phase of mitosis are sister chromatids separated and pulled to opposite poles?

anaphase

What is the correct order of the phases in the cell cycle?

Interphase, Prophase, Metaphase, Anaphase, Telophase

A final mRNA transcript of 300 nucleotides would code for ____ amino acids

100

A ______ is a three nucleotide sequence of mRNA that specifies a single amino acid

codon

During which phase of the cell cycle does the mitotic spindle form?

Prophase

What brings amino acids to the ribosome during translation?

Transfer RNA (tRNA)

What are the 2 major steps of gene expression that produce a protein from a gene?

transcription and translation

What tRNA codon is complementary to the mRNA codon GUA?

CAU

What is the role of RNA polymerase in transcription?

RNA polymerase binds to the DNA promoter and builds an mRNA molecule