cell bio exam 1

The defining property that differentiates prokaryotic cells from eukaryotic cells is their

lack of nucleus

Which of the following is a small, irregularly shaped organelle in which intracellular digestion occurs?

lysosomes

Compared to eukaryotes, prokaryotic organisms are

more abundant and more widespread on Earth.

how many MM per Micrometer?

1 mm = 1000 micrometer

How many phosphoanhydride bonds does ATP have?

2

Long polymers are made from single subunits in cells using a ___________ reaction, which ___________ water.

A condensation reaction joins two monomers together, releasing water. A hydrolysis reaction uses water to split the bond that joins two subunits of a polymer.

How do protein, nucleic acid, and polysaccharide molecules polymerize (grow in length)?

A molecule of water is lost with the addition of each monomer to the growing polymer chain. Water is removed and a new bond is created between the growing polymer and the newly added monomer.

What chemical group is found in a nucleotide but not in a nucleoside?

A nucleotide contains at least one phosphate group in addition to the base plus sugar found in a nucleoside. The phosphate group is attached at the 5' carbon.

A nucleotide is different from a nucleoside because a nucleotide has a

A nucleotide is a sugar (either ribose or deoxyribose), attached to a nitrogen-containing base, and one or more phosphate groups. A nucleoside simply lacks any phosphate groups.

Which of the following is NOT a tenet of the classical cell theory?

A. Cells are the structural and functional units of life. B. All organisms are composed of one or more cells. C. All cells arise from preexisting cells. D. ALL CELLS USE DNA AS THEIR HEREDITARY STORAGE MOLECULE

What is not true of RNA?

A. It contains a different sugar than DNA. B. *It cannot base-pair with other nucleic acids.* C. It contains a different base than DNA. D. It is usually single stranded.

Which of the following is UNLIKELY to be hydrophilic?

A. a molecule with primarily nonpolar covalent bonds Hydrophilic molecules carry positive or negative charges, allowing them to interact with the partial charges on water molecules. Polar covalent bonds form partial charges, whereas nonpolar covalent bonds do not.

Which of these is not part of the cytoskeleton?

A. actin filaments B. PLASMA MEMBRANE C. intermediate filaments D. microtubules

All amino acids have which of the following chemical groups in common?

All amino acids have an amino group (NH2) and a carboxyl group (-COOH) attached to a central carbon. They differ in which side groups are attached to the central carbon, such as a methyl group or aromatic rings, for example.

Which statement represents the cell theory?

All cells are formed by the growth and division of existing cells.

Amino acids are subunits of which of the following macromolecules?

Amino acids are subunits of proteins. Cells use amino acids to build proteins—polymers made of amino acids, which are joined head-to-tail in a long chain that folds up into a three-dimensional structure that is unique to each type of protein.

What is not a lipid?

Amino acids are the subunits from which proteins are made. Amino acids and proteins are not considered lipids, although lipids can be added to amino acids to tether a protein to a lipid bilayer. This concept will be addressed in a later chapter.

Which of the following chemical groups could confer nonpolar/hydrophobic characteristics on the region of a molecule in which it is found?

CH3 Bonds between carbon and hydrogen are nonpolar and molecules with mostly nonpolar bonds are hydrophobic. Bonds between H and electronegative atoms like O and N are polar and tend to impart hydrophilic characteristics.

Which of the following best describes flow cytometry?

Cells are passed in front of a laser, one-at-a-time, and measures size, complexity, and fluorescent properties of each cell.

Which statement is not true of chloroplasts?

Chloroplasts are present in essentially all eukaryotic cells and in certain photosynthetic bacteria. B. Each has an internal stack of membranes and is enclosed by two membranes. C. Chloroplasts contain their own DNA. D. Chloroplasts absorb light and generate oxygen and carbohydrate. E. Chloroplasts are thought to have originated from bacteria.)

Which is not a function of proteins?

Choose one: A. encasing certain viruses B. ENCODING GENETIC INFORMATION C. acting as molecular motors D. providing cells with structural support E. catalyzing biochemical reactions

Most of the organic matter in a living organism consists of macromolecules, with a much smaller contribution from the small molecules that serve as potential subunits for macromolecules.

Correct. Most of the organic matter in a living organism consists of macromolecules, with a much smaller contribution from the small molecules that serve as potential subunits for macromolecules. Small organic molecules account for only about one-tenth of the total mass of organic matter in a cell.

Covalent bonds in macromolecules are primarily important for

Covalent bonds are strong and are used within molecules to form the linkages between monomers that form the polymer. Noncovalent bonds are more important for the three-dimensional conformation and for interactions with other molecules.

Which of the following correctly describes the central dogma?

DNA → RNA → Protein

Which of the following organelles is an irregular maze of interconnected spaces enclosed by a membrane and functions as the site where most cell membrane components, as well as materials destined for export from the cell, are made?

ER

Which chemical group is found on all amino acids?

Every amino acid includes a carboxyl group and an amino group. These functional groups are part of all amino acids and they are directly involved in the creation of the peptide bond that forms the protein backbone.

Like the differentiated cells in an individual plant or animal, all bacteria have the same DNA.

FALSE; Unlike the differentiated cells in an individual plant or animal, all bacteria do not have the same DNA. Each bacterial species has its own characteristic nucleotide sequence.

What role is NOT performed by the cytoskeleton?

Generating chemical energy for the cell (A. pulling duplicated chromosomes to opposite poles in dividing cells B. transporting organelles and molecules from one place to another in the cytoplasm C. generating contraction in muscle cells D. controlling cell shape and cell movement)

Sugars are linked together when a covalent bond forms between an -OH group on one molecule and an -OH group on another. When this bond forms, what molecule is released?

H2O Sugars are linked together when a covalent bond forms between an -OH group on one molecule and an -OH group on another. This is referred to as a condensation reaction. Condensation reactions join together two molecules and release water (H2O).

What type of bond links two polynucleotide chains to each other in a double helix of DNA?

Hydrogen bonds link the two polynucleotide chains to each other in a double helix of DNA.

In water, hydrogen bonds can form between which of the following?

Hydrogen bonds often occur between hydrogen atoms and oxygen or nitrogen atoms that are held in molecules through polar covalent linkages. Thus, the intermolecular force of water, called a hydrogen bond, exists between a hydrogen atom of one water molecule and an oxygen atom of another.

Which statement is correct about base pairing in DNA?

In DNA, the common base-pairing nucleotides are: A pairs with T, and G pairs with C. The ability of the bases in different nucleic acid molecules to recognize and pair with each other by hydrogen-bonding (called base-pairing)—G with C, and A with T—underlies all of heredity and evolution.

What is a drawback to using electron microscopy?

It cannot be used to view living cells.

What is a drawback to using light microscopy?

It cannot be used to view structures smaller than a bacterium.

All cells require oxygen in order to survive.

It is false because some cells perform anaerobic respiration.

Within a developed multicellular organism, all cells possess the ability to divide and do so regularly.

It is false, because some cells lose the ability to replicate their DNA and divide.

The image below shows a polypeptide chain. Which letter best represents the N-terminus end of the polypeptide chain?

It's the NH2 next to a double bonded Oxygen

Which statement is not true of mitochondria?

Mitochondria are not present in plant cells. (A. Mitochondria contain their own DNA. B. Mitochondria have an inner and outer membrane. C. Mitochondria are involved in the chemical energy cycle of the cell. D. Mitochondria are not present in plant cells. E. Mitochondria are thought to have originated from bacteria.)

What is the general term for the simplest sugars?

Monosaccharides are sugar monomers with the general formula (CH2O)n. These are described as the simple sugars and the term monosaccharide encompasses all of the simple sugars.

Which of the following is an inorganic compound?

Organic compounds are made up of carbon atoms linked together, frequently along with other atoms and chemical groups. Inorganic compounds do not contain multiple linked carbon atoms.

What type of bond links nucleotides in a nucleic acid chain?

Phosphodiester bonds join the sugar and phosphate groups in the backbone of a nucleic acid chain. This bond forms between the 5' phosphate group of one nucleotide and the 3' hydroxyl group of the neighboring nucleotide.

Polysaccharides, proteins, and nucleic acids are made from monomeric subunits. What are they?

Polysaccharides, proteins, and nucleic acids are made from monomeric subunits. Each macromolecule is a polymer formed from small molecules—called monomers or subunits—that are linked together by covalent bonds. Glucose is an example monomer of a polysaccharide, alanine is an example monomer of a protein, and guanosine triphosphate is an example monomer of nucleic acid.

Self-replication of living cells occurs through the catalytic action of

Proteins; To self-replicate, cells must first replicate their DNA, followed by division in two. DNA replication is performed by enzymes, which are proteins.

What is one of the main differences between DNA and RNA?

RNA uses the sugar ribose, which has a 2ʹ and a 3ʹ −OH, whereas DNA uses the sugar deoxyribose, which only has a 2ʹ −OH. This leads to fundamental differences in the self-replication and stability of these molecules.

Which term describes a hydrocarbon tail of a fatty acid that has no double bonds between its carbon atoms?

Saturated fatty acids contain no instances of double bonding in the hydrocarbon chain. The carbons in these hydrocarbons are completely saturated with hydrogens.

Which of the following does not contain sugars?

Steroids are lipids that include multiple carbon-containing rings. The steroid does not contain any carbohydrate (sugar) chemistry.

Which of the following is a role that sugars can play outside of their role in energy production and storage?

Sugars play many roles outside of being an energy source that is stored and/or harvested for powering cellular processes. Sugars also form support structures like cell walls, exoskeletons, or adherent structures on the cell surface.

Which of the following occurs by bringing nonpolar surfaces together to exclude water?

Surfaces with nonpolar bonds cannot favorably interact with water. These hydrophobic surfaces prefer to come together to exclude water. This is referred to as hydrophobic force.

Which of the following is NOT special about the chemistry of life?

The chemical reactions that occur in living organisms are exclusively oxidation-reduction reactions.

The chemical reactions that take place in a cell, as compared to the chemistry in nonliving matter, primarily occur

The chemistry of living things follows all the same chemical and physical laws of the chemistry that occurs in the nonliving world. The difference is that the chemical compounds of life are mostly carbon-based polymers that undergo complex reactions in an aqueous environment.

When comparing liver cells and kidney cells within an organism, many differences can be observed and documented. Which of following is not a difference between liver cells and kidney cells in the same animal?

The different cells have different DNA.

Why do phospholipids aggregate to form cell membranes?

The hydrophobic regions cluster at the membrane's center, where they can avoid contact with water, while the hydrophilic portions face the outside of the membrane, where they interact with water. This is amphipathic.

What is the covalent linkage between two adjacent amino acids in a protein called?

The peptide bond is the covalent linkage between two adjacent amino acids in a protein. Peptide bonds link the amino group of one amino acid with the carboxyl group of another.

You classify the mutation as a loss-of-function mutation. What affect would you expect for this mutation to have on the protein?

The protein resulting from the mutant DNA sequence will likely have a distorted shape that will result in a loss of its function compared to the wild-type protein.

You classify the mutation as a gain-of-function mutation. What affect would you expect for this mutation to have on the protein?

The protein resulting from the mutant DNA sequence will likely perform "better" than the wild-type protein.

What reaction involving ATP releases a large amount of energy?

The release of the terminal phosphate group from ATP releases a large amount of energy. The breaking of the phosphoanhydride bonds releases a large amount of useful energy for the cell.

Which of the following is NOT TRUE concerning ribonucleotides?

They can contain thymine. (A. They are only found in RNA. B. They contain ribose. C. They contain a phosphate group. D. They can contain thymine.)

One thing all cells have in common is an ability to colonize any environment on Earth.

This statement is false. No cell is capable of colonizing any environment on Earth. Although living cells have expanded to fill every conceivable habitat on Earth, most cells are capable of thriving in a single, specific environment. A bacterium adapted for life in the human gut, for example, would not survive in a hot spring or an Antarctic lake.

The shapes of most biological macromolecules are maintained largely by strong covalent bonds that form between different regions of the polymer chain.

This statement is false. The shapes of most biological macromolecules are not maintained largely by strong covalent bonds that form between different regions of the polymer chain. Rather, the conformation of macromolecules is specified in large part by the noncovalent bonds that form between different regions of the polymer chain.

is this strand DNA or RNA

This strand of nucleic acid is DNA. This is evident because of the presence of thymine and also because the sugars are deoxyribose sugars with an H, not an OH, group at the second carbon of the sugar.

Which way do the fatty acid tails of a phospholipid face in a cell membrane?

To form cell membranes, phospholipids form a bilayer, with the fatty acid tails facing each other. Thus, one layer has the fatty acid tails facing inward and the other layer has the fatty acid tails facing outward.

What do eukaryotic cells have that prokaryotes lack?

a nucleus and membrane-bound organelles

Which term best describes a fatty acid?

amphipathic Fatty acids contain some regions that interact favorably with water and other regions that interact unfavorably with water. Is water polar or nonpolar? Fatty acids contain both hydrophilic and hydrophobic regions, a property that makes them amphipathic.

The genes in the genome of an adult organism

are expressed or silenced depending on whether a gene is needed in that cell type and environment.

The main function of the nucleus is to

house the DNA in a separate cell compartment.

A segment of DNA in the genome that is not a protein-coding gene

can be used to regulate gene activity.

Which of the following is NOT a type of data output of a flow cytometer?

cell shape

Antibiotics tend to target features that are unique to bacterial cells and absent from eukaryotic cells such as our own. Which of the following would present a safe target for a new antibiotic?

cell wall

Hydrophilic molecules...

dissolve in water

Which structure could not be seen using an electron microscope?

electron

What is the name of the process by which eukaryotic cells engulf material captured from an external medium?

endocytosis

Genetic changes followed by selection are best described as the fundamentals of what process?

evolution

The inner membrane of the mitochondrion appears ___________ because it provides___________.

folded; a large surface area for staging energy production processes

Hydrophobic molecules...

form few or no hydrogen bonds with water.

Molecules composed of a small oligosaccharide covalently linked to a phospholipid are called...

glycolipids

Which of the following is a stack of flattened membrane-enclosed sacs that receives molecules made in the endoplasmic reticulum, often chemically modifies them, and then directs them to the exterior of the cell or to various locations inside the cell?

golgi apparatus

If a gene sequence in one organism is highly similar to the sequence of another gene in another organism it is called

homologous

Which type of bond makes it possible for a macromolecule to interact with great specificity with just one out of the many thousands of different molecules present inside a cell?

non-covalent bonds

Which cellular component separates the DNA of eukaryotic cells from the cytoplasm?

nuclear membrane

DNA molecules are made from monomers called...

nucleotides

Which of the following organelles are composed of more than one biological membrane?

nucleus, chloroplasts, mitochondria

Lysosomes and peroxisomes both perform a series of reactions to break down molecules, but one difference between them is that

peroxisomes contain hydrogen peroxide.

A readily available source of energy that cells use to drive reactions is stored in the ___________ bond.

phosphoanhydride. (Nucleotide triphosphates, notably ATP, have three phosphoanhydride which can be hydrolyzed easily to release energy.)

What is the name used for a molecule in which two carbons of glycerol are attached to fatty acid chains, and the third carbon is attached to a phosphate group?

phospholipid Glycerol molecules have three carbons attached to -OH groups that can be linked to fatty acids or other molecules. When two fatty acids and a phosphate are attached to glycerol, it is called a phospholipid. If three fatty acids are attached, it is called a triacylglycerol.

Which carbohydrates contain hundreds or thousands of sugar subunits?

polysaccharide Glycogen and starch are examples of polysaccharides used for storing glucose. These polymers are carbohydrates that contain hundreds or thousands of sugar subunits. Polysaccharides are not limited to just glycogen and starch, as other simple sugars can assemble into large polymers as well.

Which of these cannot be resolved with a conventional light microscope?

ribosome

Which of the following microscopy techniques would allow the most detailed image showing the 3-D structure of a flagellum?

scanning electron microscopy (this is the 3D black and white little thing with teeth)

One piece of evidence indicating that chloroplasts evolved from engulfed photosynthetic bacteria is

that they contain their own DNA.

Which phosphate below is the γ-phosphate?

the furthest one from the sugar

Which phosphate below is the α-phosphate?

the one attached to the oxygen thats attached to the ring

Which letter best represents the C-terminus end of the polypeptide chain?

the one with the C double bonded to O and single bond to OH

Forward scatter is a measure of...

the size of a cell

Which structure or process mediates the exchange of materials between the endoplasmic reticulum, Golgi apparatus, the lysosomes, and the outside of the cell?

transport vesicles

The cell components that move materials from one organelle to another are called

transport vessicles

Organisms that have inherited their genetic instructions from a common ancestor share the same DNA sequence.

true