Chapter 3

¡Supera tus tareas y exámenes ahora con Quizwiz!

Ribosomes

site of protein synthesis

Which class of RNA molecules codes for the entire sequence of a protein?

Messenger RNA

Water is essential nutrient

True

carbohydrates, fats, and proteins can all be broken down and used by cells to produce ATP>

True

When a protein is no longer needed by he cell, it can be tagged for degradation by the addition of a small peptide called _______________.

Ubiquitin

A three base sequence on mRNA is called a(n) _______.

codon, triplet, triplet codon, or DNA triplet

The amount of solute that is crossing a surface in either direction in a given amount of time is known as ___________________.

flux

Regulatory proteins turn these on and off in accordance with changing needs for the proteins they encode.

genes

Molecules of substances within solids, liquids, and gases are in constant motion, and the source of energy causing this motion is ______.

heat

DNA is a long threadlike molecule composed of subunits called ____.

nucleotides

Carrier proteins that directly require the hydrolysis of ATP to function mediate which process?

primary active transport

What are the products of the aerobic catabolism of glucose:C6H12O6+ 6O2

6CO2 + 6H20 = 686 kcal/mol

Primary active transport is directly achieved by hydrolysis of _____.

ATP

Three letter word abbreviation for the molecule that is the main cellular energy source created from the metabolic breakdown of carbohydrates, proteins, and fats is———

ATP

The enzyme in the inner mitochondrial membrane that catalyzes the addition of a phosphate to adenosine diphosphate (ADP) is

ATP synthase

Which of the following proteins forms a channel in the inner mitochondrial membrane, allowing the hydrogen ions to flow back to the matrix side?

ATP synthase

Integral proteins that allow ions to diffuse through the membrane are called ion _________.

Channels or channel

Molecules of any substance, whether solid, liquid, or gas, are in a _____________ state of movement or vibration, and such movement is _____________.

Continuous; random

Cells employ two mechanisms to selectively alter protein shape. The mechanism shown here is called _______ modulation

Covalent

TRUE OR FALSE. The energy for simple diffusion comes from ATP.

FALSE

Liver cells are able to break down glycogen into glucose, thus causing the intracellular glucose concentration to become higher than the extracellular glucose concentration.What happens to facilitated diffusion of glucose under these conditions?

Facilitated diffusion causes net movement of glucose out of the liver cells.

Mutation refers to a change in the structure or function of a protein.

False

The mRNA molecules are transported from the nucleus to the cytoplasm via passive diffusion.

False

A ribosome consists of three subunits, each of which is made up of proteins and ribosomal RNA.

False ( there are

The law that relates the rate of mass diffusion to the concentration gradient is ______ law of diffusion.

Fick's

Chromosome

Is a complex of DNA and protein carrying the genetic material of a nucleus. A gene is a segment of DNA that codes for the production of a molecule of RNA, which in most cases codes for one or more proteins.

Chromatin

Is the filamentous material in the interphase nucleus, composed of DNA and associated proteins. A gene is a segment of DNA and associated proteins. A gene is a segment of DNA that codes for the production of a molecule of RNA, which in most cases codes for one or more

Replication

Is the process of making a exact copy, as occurs with DNA replication prior to mitosis

In this light micrograph of a blood sample of a person, the red blood cells indicated with a ? are best described as

Sickled, sickle, sickle shaped

The exchange of oxygen an carbon dioxide gases occurs through which type of transport mechanisms?

Simple diffusion

For each molecule of ATP hydrolyzed, the Na+/K+-ATPase pump moves ______ sodium ions out of cell and ______________ potassium inons into a cell.

Three; two

The type of intercellular junctions in which neighboring cells are connected in a band around the entire circumference of the cell, and which typically create barriers to movement of molecules between epithelial cells are known as

Tight junctions.

The process of copying the information encoded in DNA into messenger RNA is called__________.

Transcription

Building RNA from the genetic code (DNA base sequence) is the process of _______________. Producing a protein based on the sequence of a molecule of RNA is the process of ____________

Transcription; translation

During protein synthesis, the step using DNA to make mRNA is called ___________, and the step i which mRNA is "rear" to make protein is called ________.

Transcription; translation

True or False ./The diffusion of ions is influenced by the same factors that influence the diffusion of other solutes, plus the electrical forces that act upon them and the presence or lack of ion channels.

True

True or False. The lipid bilayer is highly impermeable to all charged molecules.

True

Ion channels that are activated by changes in the membrane potential are called __________-gated channels

Voltage

__________ are ion channels that open or close in response to changes in the membrane potential.

Voltage-gated channels

The strength of ligand-protein binding is a property of the binding site known as ________

affinity

The strength of the attraction between the protein and the ligand is known as _________.

affinity

The combination of the forces acting on an ion due to the concentration gradient and the membrane potential is known as the ___________.

electrochemical gradient

The final result is a molecule of _________.

mRNA

The difference in electrical charge between the inside and outside of a cell membrane is known as the _______.

membrane potential

The difference in electrical charge between the inside and outside of a cell membrane is known as the _________.

membrane potential

Which of the following factors influences the net flux of ions across the cell membrane, but does not affect the net flux of nonpolar substances?

membrane potential

The characteristic of some protein-binding sites that allows them to bind only one particular ligand is known as chemical ___________

specificity

Conversion of nucleotide sequences into amino acid sequences is known as ______.

translation

Endosomes

transport, package, and sort cell material traveling to and from the membrane

Integral proteins tend to make excellent ____________.

transporters, because they span the plasma membrane

Adipocytes store energy mainly in the form of ______

triglycerides

Peroxisomes

Break down fatty acids and produce hydrogen peroxide

Transformation

A change in genotype and phenotype due to the assimilation of external DNA by a cell.

Desmosomes

Anchoring junctions that prevents cells subjected to mechanical stress from being pulled apart; button like thickenings of adjacent plasma membranes connected by fine protein filaments

an enzyme

Biological catalyst

A three basis sequence of mRNA that specifies one amino acid is called a (n)_________.

Codon

A(n) _________ is a nonprotein, such as a metal ion or coenzyme, that is required for some enzymes to function.

Cofactor

A trace metal that is required for the activity of a particular enzyme to occur is called a(n)__

Cofactor or co-factor

Each codon in RNA is _______ in DNA.

Complimentary to a three-base sequence.

Which of the following best describes the process of transcription?

DNA - mRNA

Are intercellular junctions characterized by accumulations of "dense plaques" that serve as disk-shaped anchoring points for cadherin proteins and which create a strong physical attachment between cells.

Desmosomes

A protein catalyst that lowers the activation energy of a chemical reaction is called a(n) _____

Enzyme

enzyme-mediated reactions can be increased by increasing_______

Enzyme concentration Substrate concentration Enzyme activity

Nutrients that are required for health and that cannot be synthesized by the body in adequate amounts are reffered to as _________ nutrients

Essential

True or False:Messenger RNA (mRNA) is the only type of RNA involved in producing proteins in a cell.

F

When a woman gives birth, prolactin stimulates her mammary glands to produce casein, a protein that her body never synthesized before. This demonstrates that ___________.

Genes can be turned on or off

The term describes the 10-step pathway by which glucose is catabolized in the cytosol is ______

Glycolysis

A series of closely apposed, flattened membranous sacs within the cell that modifies proteins arriving from the rough endoplasmic reticulum and packages them into secretory vesicles is know as the

Golgi apparatus

Ingested furanocoumarins from grapefruit inhibit the enzyme CYP3A4, which causes the amount of the drug statin entering the blood to be _____________.

Greater than normal

Diffusion of polar molecules across a membrane is limited by the membrane's structure, namely its ____________.

Hydrophobic interior

Diffusion of polar molecules across a membrane is limited by the membrane's structure,, namely its__________.

Hydrophobic interior

The diffusion of substance across a membrane is limited by the chemical composition of the membrane. Specifically, the membrane has an interior that is ________________.

Hydrophobic, nonpolar or non-polar

The diffusion of substance across a membrane is limited by the chemical composition of the membrane. Specifically, the membrane has an interior that is _______________________.

Hydrophobic, nonpolar, or non-polar

Transporter of nutrients to cross the plasma membrane?

Integral proteins

During translation, mRNA does which. Of the following?

It is selectively transported through a nuclear pore and attaches to a ribosome where translation occurs. It carries the genetic code from the nucleus to the cytoplasm.

The mathematical formula for Fick's law of diffusion is ______________

J=PA(Co-Ci) or J= P X A X (Co-Ci)

Which three terms refer to the exact same process?

Krebs cycle Citric acid cycle TCA cycle

Any molecule (including another protein) or ion that is bound to a protein by electrical attractions or hydrophobic forces is called _____

Ligand

Ion channels are proteins that can usually be in one of two states. What are the names of the two states?

Open Closed

Vitamins are a group of 14 ____________ essential nutrients required in very ______ amounts in the diet.

Organic; small

Identify the substances that can easily diffuse through the plasma membrane.

Oxygen Carbon dioxide Steroid hormones Lipids

When ion channels change between their open and closed states we can see changes in the membrane's ___________ to ions.

Permeability

Nonpolar molecules diffuse much more rapidly across plasma membranes because these molecules can dissolve in the nonpolar regions of the membrane occupied by the fatty acid chains of the membrane's _______________.

Phospholipids

Nonpolar molecules diffuse much more rapidly across plasma membranes because these molecules can dissolve int he nonpolar regions of the membrane occupied by the fatty acid chains of the membrane's__________.

Phospholipids

The nuclear envelope is perforated with openings called nuclear ____________ that regulate the movement of messenger RNA through the envelope.

Pores

The nuclear envelope is performed with openings called nuclear ______ that regulate the movement of messenger RNA through the envelope.

Pores.

A negatively-charged ion will be attracted to one that is. ——————-.

Positively-charged

A separation of electrical charge across the plasma membranes of most cells is known as the membrane ___________.

Potential

The ion's electrochemical gradients results from he combination of a membrane _________ and a difference in ion ______ across a membrane.

Potential; concentrations or concentration

Proton pumps hydrolyze ATP to provide the energy to move H+ against its concentration gradient. This is an example of which type of molecular movement?

Primary active transport

Protein catabolism requires only few enzymes, collectively called __________.

Proteases

The plasma membrane is made of phospholipids and ______________.

Protein

Ribosomes are

Proteins and ribosomal RNA (rRNA)

What are components that make up ribosomes?

Proteins, rRNA

Breaking the bonds between amino acids is called__________ and is performed by enzymes called_____________.

Proteolysis; proteases

_____________ is a molecule that consist of a single nucleotide chain containing adenine, uracil, cytosine, guanine, and a sugar called ribose, whereas _______ is a double -helix molecule containing adenine, thymine, cytosine, guanine, ad a sugar called deoxyribose.

RNA;DNA

Distance is an important factor in determining the ________ at which molecules diffuse.

Rate

In a metabolic pathway, the slowest step is known as the _____________, ____________ reaction.

Rate-limiting

In multi enzyme metabolic reaction, the step that determines the overall activity of the pathway is called_________

Rate-limiting reaction

The reaction rate is influence by four factors. These are concentration of _________, ___________, energy, temperature, and the presence of a(n) ______________.

Reactants ,activation, catalyst

The complimentary shapes of ligand and the protein-binding site determine the chemical _________ of binding.

Specificity

The percent saturation of a binding site on a protein depends mainly on which two factors

The concentration of unbound ligand in the solution The affinity of the binding site for the ligand

A membrane's permeability to a molecule depends on which of the following?

The molecular weight of the molecule The lipid solubility of the molecule

Which is TRUE about facilitated diffusion across the cell membrane?

The net transport by facilitated diffusion will be zero when concentrations of a substance are equal on the two sides of the membrane.

Active transport is characterized by __________.

The requirement for energy Movement of molecules against their concentration gradient

The base adenine in DNA pairs with the base _______________ in RNA.

Uracil or U

The 14 organic essential nutrients that required in very small amounts in the diet are called ______.

Vitamins

The lipid bilayer functions as a barrier to the passage of ________-soluble molecules.

Water

Ions move across the cell membrane via

active transport, integral membrane proteins

The region of a protein to which a ligand binds is known as a __________.

binding site

In an individual who is dehydrated, the numbers of aquaporins in the membranes of the kidney epithelial cells will ___________; this will permit ______________ water to move from the urine that is being formed in the kidney ducts back into the blood.

increase; additional

The percent saturation of binding sites ___________ with increasing ligand concentration

increases

RNA splicing removes ________ from the RNA transcript.

introns

In cytoplasm "molecule T" binds to a ribosome, the cell organelle required for its translation into protein. Molecule T must be _________

mRNA, messengerRNA, or messenger RNA

The main role of ____ during protein synthesis is to carry the genetic code from the nucleus to the cytoplasm.

mRNa

Free __________ base - pair with the deoxynucleotides in the template strand of DNA

ribonucleotide triphosphates

Transcription

synthesis of an RNA molecule from a DNA template

During translation, the molecule that binds to a free amino acid in the cytosol and delivers it to the ribosome is ___________

tRNA

The process of transferring genetic information from DNA to RNA in the nucleus is known as

transcription

Two categories of active transport

primary and secondary

The type of carrier-mediated cotransport in which the energy to move a solute across a membrane against its concentration gradient is provided by the transport of sodium down its concentration gradient is called

secondary active transport

The property of ion channels to only allow certain ions to pass through them is known as __________.

selectivity or specificity

Which of these molecules are commonly used as fuel molecules to produce ATP?

Carbohydrates,fats, and proteins, glucose

gap junctions

(communicating junctions) provide cytoplasmic channels between adjacent cells

Proteasomes

A giant protein complex that recognizes and destroys proteins tagged for elimination by the small protein ubiquitin.

Gene

A segment of DNA that specifies the amino olacid sequence in a specific polypeptide chain. - A segment of DNA that a chromosome that codes for a specific trait

Golgi apparatus

A series of closely, flattened membranous sacs within the cell that modifies proteins arriving from the rough endoplasmic reticulum and packages them i to secretory

The use of energy to power the movement of substance across a membrane is commonly referred to as ______________ transport.

Active or primary active

Carbohydrates, fats, and proteins are oxidized within cells, which releases heat and transfers energy into the primary energy currency used by cells, which is the nucleotide _____________.

Adenosine triphosphate (ATP)

Most of the body's fat is stored in specialized cells known as ____________

Adipocytes

Binding sites that tightly bind a ligand are called high _______ binding sites

Affinity

Genome

All the genetic information in an organism; all of an organism's chromosomes. Remember that the genome is all the genes of one individual, estimated at 20,000-25,000 genes in humans. A gene is a segment of DNA that codes for the production of a molecule of RNA, which in most cases codes for one or more proteins

When a ligand binds to one site of a protein and changes the characteristics of a second binding site, _________ is at play.

Allosteric modulation

The two mechanism found that selectively alter protein shape are known as ____________ modulation and __________modulation

Allosteric; covalent

During translation, the role of transfer RNA (tRNA) is to bind a free __________ in the cytosol and deliver it to the ribosome where mRNA specifies the sequence of a growing polypeptide.

Amino acid

To calculate the flux you would need to know the ___________ of material and the unit of time.

Amount

Which of the following are reactants in the overall equation of glucose catabolism

C6H12O6 O2

There are three classes of energy -yielding molecules

Carbohydrates, fats, proteins

Grapefruit juice contains a number of compounds called furanocoumarins.These compounds inhibit the enzyme ______________ P450 3A4 via the mechanism of ___________.

Cytochrome; covalent modification

RNA is translated into proteins mainly in the ____________, while DNA remains in the _____________.

Cytoplasm; nucleus

The ribonucleotides, paired with the template strand of ____, are linked by RNA polymerase to form a primary RNA transcript.

DNA

Where information stored that codes for all of the proteins that can be synthesized in the body.

DNA

Which of the following best descries the process of transcription?

DNA - mRNA

Match the nucleotide bases in DNA with the RNA nucleotide bases they pair with during transcription:

DNA Adenine - - RNA Uracil DNA Cytosine —- RNA Guanine DNA Thymine - - -RNA Adenine DNA Guanine - - -RNA Cytosine

A specific molecule which binds to a channel protein and either directly or indirectly causes to the channel's shape is called a (n) ______________

Ligand

Chemical messengers will bind to _________-gated ion channels on the target cells.

Ligand

______ is a general term describing a molecule that binds to a specific region on a protein by electrical or hydrophobic forces.

Ligand

Many drugs produce their effects by competing with the body's natural _________ for binding sites.

Ligands

The function of the lipid bilayer, in terms of movement of molecules, is to _________ movement of polar substances.

Limit

Duffusion of polar molecules into and out of cells and organelles is mainly limited by the ______.

Lipid bilayer

Ions need to cross the membrane through ion channels because their membrane permeability is ____________.

Low

What are the factors that influence the magnitude of the net flux based on Fick's diffusion equation?

Membrane permeability Membrane surface area Magnitude of the concentration gradient

RNA molecules that are directly involved in producing proteins are ribosomal RNA, ___________ RNA(mRNA, and ________ RNA (tRNA)

Messenger, transfer

Three classes of RNA are required for protein synthesis: __________________ RNA, _____________________ RNA, and __________________ TNA, (No abbreviations please)

Messenger,Ribosomal; transfer

Any change in the nucleotide sequence of a coding region of a DNA molecule, often resulting in a change of structure and function in the protein produced, is known as a(n)

Mutation

Any change in the nucleotide sequence of a coding region of a DNA molecule, often resulting in a change of structure and function in the protein produced, is known as a(n)

Mutation, chromosomal mutation, genetic mutation, gene mutation, substitution or deletion

The Na+/-ATPase pump moves ____________.

Na+ and K+ against their concentration gradients, using the energy from ATP.

All cells have a primary active transporter that pumps ________________.

Na+ out of cells and K+ into cells

Characteristics of facilitated diffusion

Net flux from higher to lower concentation Uses a carrier protein 1. Specificity - certain solutes 2. Saturable -limited quantity 3. Inhibitable - drug interactions 4. Energy *In*dependent

_____________ molecules are lipid-soluble and can easily cross a plasma membrane, while ______ molecules cannot,

Non-polar; polar

Molecules of DNA contain information, encoded in the sequence of _______________, for protein synthesis.

Nucleotides

The prominent, double membrane-bound structure of the cell that stores genetic information

Nucleus

Ions with positive charge will_______ each other.

Repel

RNA nucleotides differ from those of DNA because they contain the sugar _________________ (rather than deoxyribose) and the base _______________ (rather than thymine)

Ribose; uracil

Cellular structures that serve as the problem factories of a cell are the

Ribosomes

Proteins destined to be secreted from a cell are manufactured in the ____________.

Rough endoplasmic reticulum

Protein manufactured for incorporation into cell membranes or for secretion from a cell have a 15-30 amino segment at the beginning called a(n) _________________ ___________________

SIGNAL SEQUENCE OR SIGNAL PEPTIDE

The fraction of total binding sites that are occupied at any given time is known as _______.

Saturation

Ion channels only permit certain ions to pass through them. This characteristic is known as ______.

Selectivity

A signal sequence is a specific of amino acids at the _________ of a growing polypeptide chain which targets a protein for __________

Start; secretion

An enzyme is a

biological catalyst

The ability of a protein-binding site to bind specific ligands is known as __________, and it depends only on the _______ of the binding site.

chemical specificity, shape

Another name for the Krebs cycle is ________ cycle

citric acid

When multiple ligands are available that can bind to the same binding site , ____ can occur.

competition

Addition of ubiquitin marks proteins for which of the following?

degradation

The extraction of energy from glucose occurs in several steps. The first step is _________

glycolysis

Which of the following would increase the time it takes for diffusion equilibrium to be reached between a cell's intracellular fluid and the blood plasma.

increasing the distance between the cell and the blood stream

A(n) _________ is any molecule or ion that is bound to the surface of a protein.

ligand

Diffusion of polar molecules into and out of cells and organelles is mainly limited by the ______.

lipid bilayer

Binding sites that weakly bind a ligand are called __________ binding sites.

low affinity

In a typical example of secondary active transport, the energy required for the movement of a solute across a membrane against its concentration gradient is most directly obtained from ___________.

movement of another solute like Na+ down its concentration gradient

total solute concentration

osmolarity

Carboxysomes

polyhedral bodies packed with the enzyme Rubisco for CO2 fixation


Conjuntos de estudio relacionados

Module 10-13: L2 Security and WLAN

View Set

FED GOVT Reading Quiz 6: Congress

View Set

Las Meninas es la pintura más famosa de Velázquez, y una obra maestra. En la pintura, podemos ver Velázquez, las doncellas de honor, la Infanta Margarita, un reflejo tanto del rey como de la reina, la chaperona de la infanta Margarita, el guardaespaldas d

View Set