Biology Practice Exam 1 + Need to Study
DNA isolated from a human liver cell contains 28% A. What percent will be T?
28% Equal A to T Equal C to G
If one strand of a DNA molecule has the sequence of bases 5'ATTGCT3', the other complementary strand would have the sequence...
3'TAACGA5'
Which of the following is NOT a pyrimidine? A. Adenine B. Uracil C. Thymine D. Cytosine
A. Adenine
Purines
Adenine (A) Guanine (G)
Prokaryotes can be classified as
Archaea and Baceteria
The term phospholipid is BEST described by which of the following statements? A. A nonpolar lipid molecule that is made polar by the addition of a phosphate group B. A nonpolar lipid that is made amphipathic by the addition of a phosphate group C. A polar lipid molecule that fully interacts with water D. A polar lipid molecule that fully repels water
B. A nonpolar lipid that is made amphipathic by the addition of a phosphate group
Which of the following effects is pro ducted by the high surface tension of water? A. Lakes don't freeze solid in winter, despite low temperatures B. A water strider can walk across the surface of a small pond C. Organisms resist temperature changes, although they give off heat due to chemical reactions D. Evaporation of sweat from the skin helps to keep people from overheating E. Water flows upward from the roots to the leaves in plants
B. A water strider can walk across the surface of a small pond
Which of the following is NOT a characteristic of DNA? A. antiparallel strands B. Primary, secondary, and tertiary structure C. Hydrogen bonds between nitrogenous bases D. Major and minor grooves
B. Primary, secondary, and tertiary structure NO tertiary structure
Which of the following is TRUE for the Watson and Crick model for DNA? A. The two strands of the DNA helix run in the same direction B. The purines (double rings) base-pair with the pyrimidines (single ring) C. The two strands of the helix are held together by covalent bonds D. The nitrogenous bases are attached to the phosphate molecule
B. The purines (double rings) base-pair with the pyrimidines (single ring)
Amphipathic
Both hydrophilic and hydrophobic portions Head-Hydrophilic Tail-Hydrophobic
Which of the following structural features is common to cellulose, chitin, and peptidoglycan? A. They are all composed of glucose in either the alpha or beta form B. They all contain peptide bonds C. The can all form bonds between polymer chains that create parallel strands D. They are all composed of highly branched fibers
C. The can all form bonds between polymer chains that create parallel strands
What is the chemical equation that summarizes the process of photosynthesis?
CO2+H20+sunlight--> CO2+O2
Aldose
Carbonyl group at end of carbon chain
Ketose
Carbonyl group in middle of carbon chain
Plant cell walls contain ___
Cellulose
Fungal cell walls contain ___
Chitin
When Pasteur tested the hypothesis of spontaneous generation, he compared the ability of a sterilized growth medium (meat broth) to produce a population of bacteria in two different types of flasks. One had a simple neck open to the outside, and the other had a "goose neck" bend that also was open to the environment. Pasteur expected that bacteria would appear in the flask with the standard neck. In this experiment, the standard neck flask served as a/an:
Control
Pyrimidines
Cytosine (C) Uracil (U) Thymine (T)
Which of the following crosses lipid bilayers the fastest? A. A sodium ion B. A small, polar molecule like water C. A large, polar molecule like glucose D. A small, non polar molecule like oxygen
D. A small, non polar molecule like oxygen
Which of the following associations are INCORRECT? A. Proteins-Peptide bonds B. Carbohydrates-Glycosidic linkages C. Nucleic acids-Phosphodiester bonds D. Lipids-Carbonyl bonds
D. Lipids-Carbonyl bonds
Cells can make polymers from monomers by ___ and this process ___.
Dehydration/condensation reactions...Requires energy
There are 20 different amino acids. What makes one amino acid different from another?
Different side chains (R groups) attached to a carbon
Osmosis
Diffusion of water Down concentration gradient Low solute to high solute PASSIVE
Lactose, a sugar in milk, is composed of one glucose molecule joined to one galactose molecule. How is lactose best classified?
Disaccharide 2 sugar units
Prokaryotic
Do not have a membrane-bound nucleus "Before the nucleus"
Which of the following terms is NOT typically associated with prokaryotic organisms? A. Nucleoid B. Peptidoglycan C. Ribosomes D. Plasmid E. Vacuole
E. Vacuole
Glycogen
Energy STORAGE in ANIMAL cells
Starch
Energy STORAGE in PLANT cells
Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells?
Facilitated diffusion
A molecule of water has the ability to hydrogen bond to a maximum of ____ other water molecules
Four
Eukartyotic
Has a membrane-bound nucleus "True nucleus"
The amino acids of the protein keratin are arranged in an alpha helix. This secondary structure is stabilized by...
Hydrogen bonds
Tonicity
Hypotonic=Low Hypertonic=High HYPO to HYPER
Lipids are synthesized...
In the smooth ER
Condensation/Dehydration Reaction
Monomer in, water out
Diffusion
Movement of molecule from region of high concentration to low concentration Concentration gradient PASSIVE Move with the gradient until in dynamic (still moving) equilibrium
Active Transport
Moves ions and molecules AGAINST their electrochemical gradients Requires energy in the form of ATP Overcome concentration gradient force LOW to HIGH
New proteins enter the nucleus through
Nuclear pores
Bacterial cell walls contain ___
Peptidoglycan
Nucleotide
Phosphate group is bonded to 5' carbon of sugar Nitrogenous base is bonded to 1' carbon of sugar
Nucleotide Monomers are linked by a...
Phosphodiester bond Attach phosphate group to 3' hydroxyl to previous nucleotide
Proteins like enzymes can lose their structure if subjected to changes in pH or temperature. What is this process called?
Protein denaturation
Nitrogenous Bases
Pyrimidines and Purines
Peptidoglycan
STRUCTURAL support in BACTERIA
Chitin
STRUCTURAL support in FUNGI and INSECTS and CRUSTACEANS
Cellulose
STRUCTURAL support in PLANTS and ALGAE
Plant lipids are typically in the liquid phase because they are ...
Saturated
What is the major structural difference between starch and glycogen?
The amount of branching that occurs in the molecule Glycogen has much more
What will happen to a red blood cell, which has an internal ion concentration of about 0.9%, if it is placed into a beaker of pure water (ion concentration is zero)?
The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC
Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages in cellulose. Why is this logical?
The geometry of the bonds is different, and the shapes of enzyme active sites are highly specific
DNase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNase?
The phosphodiester bonds between deoxyribose sugar and their phosphate groups would be broken
Water Potential
The potential energy that water has in a particular situation Water always flows from areas of HIGH potential energy to LOW potential energy Water potential= Solute potential (negative) + Pressure potential
When animal cells are placed in water they shrivel. This is because...
The water is hypertonic
DNA ONLY
Thymine
The tertiary structure of a protein is the...
Unique three-dimensional shape of the fully folded polypeptide
RNA ONLY
Uracil
Hydrolysis Reaction
Water in, monomer out
Under what circumstances does membrane transport ALWAYS require energy?
Whenever a solute needs to be moved from low concentration to high concentration through a phospholipid bilayer membrane