Chapter 3
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
