The most important advantage of transmission electron microscope (TEM) over light microscope (LM) is its higher resolution.
If a cell doubled in diameter, it would have twice as much cytoplasm to maintain.
In the plasma membrane, glycolipids and glycoproteins face toward the cytoplasm, while peripheral proteins always face toward the ECF.
A cell's second messengers serve to transport material through the plasma membrane.
Microvilli and cilia differ in their function but have the same internal structure.
Ligand-gated channels are membrane proteins that open or close in response to the binding of a chemical.
The greater the concentration gradient the faster the diffusion rate.
The Na+-K+ ATPase is a countertransport antiport carrier, which always requires energy.
The sodium-glucose transport protein (SGLT) is one example of an active transport process involving a uniport carrier.
One example of pinocytosis is the uptake of low-density lipoproteins (LDLs) by endothelial cells.
Both the nucleus and the mitochondrion are surrounded by two layers of unit membrane.
The nucleus is the largest organelle in most cells.
Ribosomes are made of proteins and RNA.
The Golgi complex makes peroxisomes but not lysosomes.
A crystal of calcium phosphate in the cytoplasm of a cell should be classified as an inclusion.
C. all cells occupy space.
All of the generalizations below constitute the modern cell theory except-
________ cells are thick in the middle and tapered toward the end.
the relationship between its volume and surface area
Most human cells range from 10 to 15 micrometers in diameter. What limits how large a cell can be?
The fluid outside of a cell is called
The flat-shaped cells found covering the skin are
producing higher resolution.
Although the transmission electron microscope (TEM) can magnify much more than a light microscope, even at identical magnifications
the TEM has the advantage of
______ are the most abundant molecules in the plasma membrane.
_____ are membrane proteins that bind to signals by which cells communicate.
A receptor protein in the plasma membrane will not bind to just any chemical in the extracellular fluid, but only to certain ones. That is to say, the receptor exhibits
In its second-messenger role, cAMP activates enzymes called ______, whose job is to regulate other enzymes by adding phosphate groups to them.
Transmembrane proteins that make up enzymes in the plasma membrane are made up of hydrophilic and hydrophobic regions. Most amino acids embedded in the membrane are ________, while most amino acids facing the extracellular fluid are __________.
water in the extracellular fluid.
Gates respond to all these stimuli except
______ act like identification tags in the glycocalyx that enable the body to distinguish its own cells from foreign and diseased cells.
Flagella; cilia; microvilli
______ provide motility to a cell, ______ act as sensory "antenna" in many cells, and ____________ increase a cell's surface area.
Cells lining the small intestine are specialized for absorption of nutrients. Their plasma membrane has
a peripheral protein
This figure shows the plasma membrane. What does "A" represent?
This figure shows the plasma membrane. What does "C" represent?
This figure shows the plasma membrane. What does "D" represent?
_____________ consume ATP when transferring solutes from one side to the other side of the plasma membrane.
water will pass down its concentration gradient from solution B to A.
Two solutions are separated by a selectively permeable membrane. If solution A has a higher concentration of a nonpermeating solute than solution B, then,
Filtration; hydrostatic pressure
_____________ is the process in which ____________ forces water and small solutes such as salts through narrow clefts between capillary cells.
Water flows through a selectively permeable membrane in a process called __________, but water molecules cross the membrane more easily through channels of transmembrane proteins called __________.
Insulin is taken up by endocytosis by endothelial cells lining capillaries, and then transported across the cell to the other side, where it is released. This transport is called
Sodium and glucose are transported together from the intestinal lumen into an intestinal cell. The carrier protein is a(n) __________ and the process is called ____________.
up; active transport
The sodium-potassium (Na+-K+) pump transports both sodium and potassium __________ their concentration gradients in a process called ____________.
A red blood cell is placed in a hypertonic solution. The concentration of solutes in the solution is __________ than the concentration of solutes in the intracellular fluid and will cause the cell to ______________.
are cases of carrier-mediated transport.
Facilitated diffusion and active transport have in common that both
______ describes the number of particles of a solute in a solution, whereas ______ is the ability of a solution to affect the fluid volume in a cell.
Which of the following processes could occur only through the plasma membrane of a living cell?
Particles can leave a cell by any of these means except by
White blood cells engulf bacteria by means of
transport of Na+ into the cell and K+ out of the cell.
The Na+-K+ pump has the following functions except
A patient was severely dehydrated, losing a large amount of fluid. The patient was given intravenous fluids of normal saline. Normal saline is ________ to your blood cells and is about __________ NaCl.
transport of Na+ from a place of low concentration to a place of higher concentration
Which of these is an example of active transport?
Which of these bring nonspecific material into a cell?
These are all membranous organelles except
smooth endoplasmic reticulum.
Among other functions, hepatocytes (liver cells) are specialized in detoxifying drugs or other chemicals. Hepatocytes have large amounts of
What function would immediately cease if the ribosomes of a cell were destroyed?
What organelle is most active in causing programmed cell death?
Muscle cells contain numerous _____________ to serve their high demand for ATP.
smooth endoplasmic reticulum
This organelle synthesizes steroids in the ovary and stores calcium in muscle cells.
______ play an important role in cell division, and they are made of __________.
The Golgi complex; rough ER
________________ synthesize(s) carbohydrates and put(s) finishing touches on proteins synthesized at ____________.
______ decompose fatty acids, and detoxify alcohol, free radicals, and drugs.
___________ is not involved in protein synthesis.
____________ gives structural support, determines the shape of a cell, and directs the movement of substances through the cell.
This figure shows the structure of a representative cell. What does "A" represent?
This figure shows the structure of a representative cell. What does "D" represent?
This figure shows the structure of a representative cell. What does "C" represent?
This figure shows the structure of a representative cell. What does "B" represent?
Naked DNA is called chromatin
DNA is composed of double-ring nitrogenous bases, whereas RNA is composed of single-ring
A gene can be defined as an information-containing segment of RNA that codes for the production of a polypeptide
Although all cells synthesize phospholipids, there are no genes for phospholipids
DNA never migrates from the nucleus to the cytoplasm to participate directly in protein synthesis
The enzyme RNA polymerase participates in translation
There are three codons that do not code for any amino acid
All proteins made by the ribosomes are exported from a cell for use elsewhere in the body
A cell starting prophase has 92 molecules of DNA in its nucleus
After mitosis each chromosome consists of two parallel filaments called sister chromatids
Mitosis is responsible for embryonic development and tissue growth
Many genes occur in alternative forms called alleles
Phenotype is the result of genetic influences only
Oncogenes and tumor-suppressor genes have similar effects on cell division
Eye color is a normal polygenic trait
nucleotides; nitrogenous base
DNA is a polymer of ______________________, which consist of a sugar, a phosphate group, and a ___________________.
If a DNA molecule were known to be 22% thymine (T), what would be the percentage of guanine (G)?
carbon, nitrogenous base, nucleotide, DNA, chromatin
Which of these is the correct sequence from simpler to more complex?
A __________ is composed of a granular cluster of eight proteins called ___________ with DNA wound around them, plus a short segment of linker DNA.
_______________________ is the DNA base sequence complementary to the strand TGCCAT.
A ________________________ contains the necessary information for the production of a molecule of RNA.
All the DNA in one 23-chromosome set is called
about 35,000 genes
The human genome consists of
Copying genetic information from DNA into RNA is called ______________, whereas using the information contained in mRNA to make a polypeptide is called _______________.
All of the following are directly involved in translation except
Transcription occurs in the ______________, but most translation occurs in the _____________.
_____________ are turned on or off by regulatory proteins in accordance with changing needs for the _____________ they encode.
tRNA, mRNA, and DNA
Anticodons, codons, and base triplets correspond to ________________, respectively.
After translation, a protein may undergo structural changes called ________________ modifications.
Enzymes encoded by genes synthesize these products.
Since there are no genes coding for carbohydrates, nucleic acids, or lipids, how do cells produce them?
mRNA codons; 64 amino acids
The genetic code is the correspondence between the _______ and the ______ that they represent.
rough ER → Golgi complex → Golgi vesicle → extracellular fluid
You were able to radioactively tag and thereby trace an amino acid that is used to make insulin,
a hormone that will be exported out of the cell. The pathway of the tagged amino acid would be
The gene coding for a polypeptide made of 51 amino acids would have a minimum number of
the molecule that carries base triplets
This figure shows translation of mRNA. What does "A" show?
a newly synthesized polypeptide
This figure shows translation of mRNA. What does "E" show?
tRNA bound to one amino acid
This figure shows translation of mRNA. What does "C" show?
DNA polymerase is most active in
G1, S, and G2 phases are collectively called
All of the following participate in DNA replication except
Cytokinesis overlaps with which phase of mitosis?
a change in DNA structure that might be beneficial, harmful, or neutral
A mutation is
ach daughter DNA consists of one new helix and one old helix
DNA replication is called semiconservative because
DNA helicase; DNA polymerase
______ opens up one segment of the DNA helix during replication, whereas ______ adds complementary free nucleotides to the exposed DNA strand.
a mistake made by the RNA polymerase
All these can cause a mutation except
growth factors; contact inhibition
Cell division is stimulated by _______________ and suppressed by ____________.
The stage at which chromosomes aggregate along the equator of a cell is
The cell synthesizes proteins and grows
Which of these processes occurs during a cell's first gap (G1) phase?
Sister chromatids are pulled to opposite poles of a cell during
Chromatin shortens and thickens, coiling into compact rods during
prophase, metaphase, anaphase, telophase, cytokinesis
Which of the following omits some stage(s) of the cell cycle?
A karyotype shows the _________ chromosomes sorted and isolated from a cell in ________.
All these are found in the karyotype of a normal human male, except
A cell finishing mitosis has ________________ DNA molecules, while a cell finishing DNA replication has ______________ DNA molecules.
If one allele is not phenotypically expressed in the presence of another, we say that it is a(an) ________________ allele.
a son who has hemophilia inherited the allele from his mother.
Hemophilia is caused by a sex-linked recessive allele. This means that
Eye color is caused by genes at multiple loci. This phenomenon is called
Germ cells have ___________ unpaired chromosomes and are thus called _________ cells.
The allele for cleft chin (C) is dominant to the allele for uncleft chin (c). A male and female who
are both heterozygous for cleft chin have a child. What is the chance that this child will have an uncleft chin?
The alleles possessed by all members of a population collectively are called the
In familial hypercholesterolemia, individuals with two abnormal alleles die of heart attacks in childhood, those with only one abnormal allele typically die as young adults, and those with two normal alleles have normal life expectancies. This exemplifies
somatic cells; 23 pairs of chromosomes; diploid
All of the body's nonreproductive cells, called ____________, usually have __________ and
are thus called _________ cells.