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Question
Why are fossils older than 60 000 years hard to date using C14?Answer
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Related questions
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Four of the five structures listed below are associated with membranes. Select the exception.
a. endoplasmic reticulum
b. granum
c. plasma membrane
d. chromosome
e. nuclear envelope
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Four of the five items listed below are organelles found in eukaryotic cells. Select the exception.
a. mitochondrion
b. Golgi body
c. nucleoid
d. lysosome
e. vacuole
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Which of the following is not a property of living things?a. They can change over generations.b. They use DNA as the genetic material.c. They change over their lifetime.d. They engage in processes to maintain homeostasis.e. All of these are true
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Which of the following is true of the structure labeled "B"?a. It is composed of tubulin subunits.b. It is composed of actin subunits.c. It is a microtubule.d. It is an intermediate filament.e. It is found in cells that give rise to nails and hair.
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The area labeled "A" isa. a nucleus.b. chromatin.c. endoplasmic reticulum.d. a vacuole.e. a nucleolus.
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Which of the following is one of the two main functions of the nuclear envelope?a. provides residence for ribosomesb. allows separation of DNA from cytoplasm machineryc. provides total isolation of nuclear componentsd. enables faster cell divisione. enables larger cell size
Q:
The best microscope to use to view internal features of specimens is the
a. basic light microscope.
b. phase contrast light microscope.
c. Nomarski process light microscope.
d. scanning electron microscope.
e. transmission electron microscope.
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Bacteria in the intestinal tract prevent pathogens from causing disease by
a. crowding them out.
b. eating other bacteria.
c. producing protein traps to kill them.
d. submerging them in acid in the stomach.
e. doing all of these.
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Explain why vigorous exercise in warm weather could be hazardous to your enzymes?
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What property of phospholipids allows them to form cell membranes?
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A __________ is a term given to a macromolecule (large molecule) made up of individual subunits.
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The following are basic building blocks of biopolymers. Match the building blocks with the statements below.a. amino acidb. glucosec. glycerold. fatty acide. nucleotideThe basic unit of glycogen
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The following are basic building blocks of biopolymers. Match the building blocks with the statements below.a. amino acidb. glucosec. glycerold. fatty acide. nucleotideThe basic unit of RNA
Q:
The following are chemical functional groups that may be part of a biologically active molecule. Answer the questions by matching the items with the most appropriate group.a. -COOHb. -CH3c. -NH2d. -OHe. f. -PO43-g. -CHOThe group that distinguishes glucose from fructose
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The following are chemical functional groups that may be part of a biologically active molecule. Answer the questions by matching the items with the most appropriate group.a. -COOHb. -CH3c. -NH2d. -OHe. f. -PO43-g. -CHOThe methyl group
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The following are chemical functional groups that may be part of a biologically active molecule. Answer the questions by matching the items with the most appropriate group.a. -COOHb. -CH3c. -NH2d. -OHe. f. -PO43-g. -CHOThe group that occurs repeatedly in sugars
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Choose the one most appropriate item from its description.a. a six-carbon sugarb. found in DNA and RNAc. principal components of cell membranesd. affect metabolic reaction ratesGlucose
Q:
Amino acids are linked by what kind of bonds to form the primary structure of a protein?
a. disulfide
b. hydrogen
c. ionic
d. peptide
e. none of these
Q:
In the figure above, the honeycomb on which the bee is standing is made up primarily of which of the following:
a. carbohydrates
b. nucleotides
c. proteins
d. lipids
e. amino acids
Q:
Triglycerides are
a. carbohydrates.
b. nucleotides.
c. proteins.
d. neutral fats.
e. amino acids.
Q:
Which of the following does NOT describe some aspect of polysaccharides?
a. energy storage
b. straight or branched chain
c. glucose subunits
d. contain only carbon, hydrogen, and oxygen atoms
e. produced by condensation reactions
Q:
Glucose and fructose
a. form rings with the same number of carbon atoms.
b. both have two oxygen atoms as part of their ring structure.
c. are alike in that both have identical functional groups.
d. contain the same number of hydrogen atoms and hydroxyl groups.
e. are disaccharides.
Q:
Oligosaccharides include
a. sucrose.
b. glucose.
c. fructose.
d. lactose
e. both sucrose and lactose.
Q:
Fructose and glucose are
a. isotopes.
b. monosaccharides.
c. disaccharides.
d. six-carbon sugars.
e. both monosaccharides and six-carbon sugars.
Q:
Monosaccharides may be characterized by all EXCEPT which of the following?
a. a ketone group
b. carbon, hydrogen, and oxygen in a 1:2:1 ratio
c. a backbone of five to six carbon atoms
d. one carbonyl group
e. the presence of glycerol and fatty acids
Q:
Although carbon dioxide contains carbon, it is not considered an "organic" compound because
a. it is not found in the earth's crust.
b. it is not present in living cells.
c. the carbon atom is not bonded to at least one hydrogen atom.
d. the carbons are not in chains or rings.
e. it is too small.
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Fats are major constituents of
a. proteins.
b. genes.
c. photosynthesis.
d. cell membranes.
e. all of these.
Q:
Isotopes of atoms
a. are electrically unbalanced.
b. behave the same chemically and physically but differ biologically from other isotopes.
c. are the same physically and biologically but differ from other isotopes chemically.
d. have the same number of protons but a different number of neutrons.
e. are produced when atoms lose electrons.
Q:
Which is the smallest unit of an element that retains the properties of the element?
a. atom
b. compound
c. ion
d. molecule
e. mixture
Q:
The ability of a solution to resist changes in pH depends on its ______________.