Biology Test 1
Which is a benefit of sexual reproduction over asexual reproduction?
The interaction of the genes from both parents brings about genetic variation
Proteins made on ribosomes may be further modified within which organelle?
Golgi complex
Which description best illustrates the product of a chemical reaction?
It is generally written on the right side and is the substance generated by the reaction
Which organic compound is not only responsible for energy storage, but also can provide thermal insulation?
Lipids
In living organisms, chemical reactions responsible for growth, repair, and nutrition are collectively referred to as...
Metabolism
DNA must transcribe its information into what type of molecule before leaving the nucleus and entering the cytoplasm?
mRNA
Amyloplasts are organelles that store...
Starch
Which best describes a result of sexual reproduction?
Two sex cells combine to form a fertilized cell
What substance is removed during a condensation reaction?
Water
How do phospholipids in vegetable oil differ from those of animal fat?
the fatty acid tails bend
What large molecules are essential in determining the structure and function of cells and tissues?
Proteins
You discover an organism that is eukaryotic, unicellular, and photosynthetic. Based on the evidence, to which group would you assign this organism?
Protist group
Which event illustrates evaporative cooling?
Sweat evaporating from the skin
How does the scanning electron microscope differ from the transmission electron microscope?
The SEM gives a 3-dimensional image of the object being studied
What is the OH- concentration of a solution having a pH of 2?
1 X 10^-12
Which description illustrates the tertiary structure of a protein molecule?
3-dimensional shape of an individual polypeptide chain
How many molecules are present in one mole of C6H12O6?
6.02 X 10^23 molecules
Which description illustrates an amphipathic molecule?
A phospholipid with both a hydrophobic end and a hydrophilic end
In the experimental evaluation of a new drug, what is the purpose of a placebo?
A placebo removes the potential psychological bias of the patient in the study
What does an ABC transporter use to transport larger ions and molecules across the cell membrane?
ATP
When a small amount of hydrochloric acid (HCl) is added to a solution of Na2HPO4, the pH of the solution does not change markedly. The pH also does not change drastically when a small amount of sodium hydroxide (NaOH) is added to this same solution. Based on these observations, the compound Na2HPO4 is:
Acting as a buffer
What differentiates an organic compound from an inorganic compound?
An organic compound contains carbon
If tyrosine and isoleucine undergo condensation, where does the new bond form?
Between carbon of the carboxyl group and the nitrogen of the amino group
To which Phylum do humans belong?
Chordata
What type of molecule carries the hereditary information of an organism?
DNA
You want to determine the location of a specific protein in a cell using a color stain. Which of the following is the best technique for this purpose?
Fluorescence microscopy
Which organelle can be considered a sorting, processing, and packaging center?
Golgi complex
The cohesiveness between water molecules is due largely to:
Hydrogen bonds
Why is ATP important in living organisms?
It can transfer some of its energy to other chemicals
What does the process of differential centrifugation achieve?
It separates components of the cell that have different densities
Which substance is an example of a very strong acid?
Lemon Juice
The primary purpose of homeostasis is to...
Maintain a constant internal environment
During an infection, white blood cells travel to the infected site and phagocytize the pathogens. After phagocytosis, primary lysosomes fuse with the phagocytic vesicle to form a larger vesicle called a secondary lysosome. The purpose for this process is to:
Mix the pathogens with strong hydrolytic enzymes and destroy them/coat the bacteria in lipids derived from the Golgi complex, which cover and smother them
What enzyme in the ER lumen catalyze the efficient folding of proteins into proper conformation?
Molecular chaperones
A liquid with a pH of 7 is considered a(n) _____ solution
Neutral
A DNA molecule is made up of...
Nucleotides
Similar families of organisms are next grouped together in the same...
Order
One of the conclusions drawn from Darwin's theory of evolution is that...
Organisms living today descended with modifications from previously existing forms
What organic molecules is the primary structural component of cell membranes?
Phospholipids
What is one cellular characteristic found in all prokaryotic and eukaryotic cells?
Plasma membrane
Which carbohydrate is the most structurally complex?
Polysaccharide
All of the members of the same species occupying the same area at the same time constitute a(n):
Population
Which is a property of unsaturated fats?
They are generally liquid at room temperature
During an experiment, what is the purpose of a control group?
To compare results to the experimental group with the variable being tested
What is the purpose of regulatory proteins?
To control the expression of specific genes
Peripheral proteins are linked to either surface of the plasma membrane by
bonding to integral proteins through noncovalent interactions
What two organelles are both responsible for converting energy into forms that can be used by cells?
mitochondria and chloroplast
If phospholipids form a spherical structure when placed in water, then which of the following is the most logical conclusion about those phospholipid molecules?
they are cone-shaped
Plants lack organ systems for disposing of toxic metabolic waste products. Their cells' vacuoles are like what animal cell organelle?
Lysosomes
What is the ultimate source of genetic variation within a population?
Mutations in DNA
What type of bond is formed if one atom is more electronegative than the other atom?
Polar covalent
Which process is most directly associated with the theory of evolution?
Populations changing over time
Which molecule is least likely to cross a cellular membrane by simple diffusion?
Potassium ion
How can we identify a particular element?
By its number of protons
Which statement about centrioles is false?
They have a 9+2 arrangement of microtubules
A hypothesis can best be described as a(n):
Tentative explanation
Why are hydrocarbons considered nonpolar?
The covalent bonds between hydrogen and carbon are nonpolar
What type of molecule can rapidly cross a plasma membrane?
small, hydrophobic molecules
Which functional group forms bridges to help stabilize a protein's quaternary structure?
Sulfhydryl
_____ are loosely associated with the phospholipid bilayer, whereas ____ are tightly bound to it.
Peripheral proteins; integral proteins
The term "fluid mosaic model" refers to the...
movement of lipids and integral proteins within the lipid bilayer
The following would be characterized as _______ based on the chemical properties of its side chain.
nonpolar
As water boils and turns to steam, what happens to the hydrogen bonds?
The hydrogen bonds break
What type of protein accelerates the thousands of different chemical reactions that take place in an organism?
Enzyme
Which of the following would most likely form electrolytes in water?
An inorganic compound
Evidence that all living cells have a common origin is best illustrated by the:
Basic similarities in cell structure and chemistry
Using the Linnean system of nomenclature, corn is named zea mays. What is the specific epithet in this name?
Mays
Why can table salt (NaCl) dissolve easily in water?
The partial positive charge of the hydrogens in the water molecule can associate with the negative charge of the oxygen of the water molecule can associate with the positive charge of the sodium atom
Which statement best describes "biology"?
The science of life
Which statement best describes the activity of the sodium-potassium pump?
it transports 3 sodium ions out of the cell in exchange for 2 potassium ions
What have studies of glucose transport in liposomes revealed?
the binding of glucose triggers a conformational change in the carrier protein
A chlorine atom has 17 protons and 18 neutrons. What is its atomic mass?
35 amu
What would be the ultimate effect on an ecosystem if decomposers were eliminated?
All life would eventually cease as nutrients would no longer be available
Which statement best describes cell theory?
All living organisms are composed of basic units called cells
Which statement best describes autotrophic organisms?
Autotrophs synthesize complex molecules from CO2, water, and energy
What is an end product of cellular respiration?
Carbon dioxide
When we know what kinds of ________ are present in an organic compound, we can predict its chemical behavior.
Functional groups
Information in living organisms is transmitted by which mechanisms?
Genes, hormones, and neurotransmitters
Which characteristic of water molecules directly contributes to insects remarkable "water walking" success?
Hydrogen bonds
Which of the following is responsible for the alpha-helical structure of proteins?
Hydrogen bonds
Which component becomes oxidized in the following chemical reaction? 4Fe + 3O2 = 2Fe2O3
Iron
Unlike lipids, hydrophilic functional groups typically contain _________ atoms, which make them more soluble in water.
Oxygen
Which component is the oxidizing agent in the following chemical reaction? 4Fe + 3O2 = 2Fe2O3
Oxygen
If a toxin, such as a bacterial toxin, destroys ribosomes, what cellular activity will be affected first?
Protein synthesis
A base is defined as a(n) _______ acceptor.
Proton
What does the nucleolus, within the nucleus, synthesize?
Ribosomal RNA
Identify 3 of the 5 basic themes in biology
The evolution of life, the interactions of living systems, and the transmission of bacteria
Which statement about van deer waal interactions is false?
They are very strong
Which of the following statements about phospholipids is false?
They contain 3 fatty acid chains
Which substance correctly identifies a reactant in the following chemical equation? CO2 + H20 = H2CO3
Water
An atom X contains 14 protons, 13 electrons, and 12 neutrons, and atom Y contains 14 protons, 14 electrons, and 12 neutrons. What can you conclude?
X and Y are atoms of the same element
What cellular structure is unique to plant cells and some photosynthetic fungi?
chloroplasts
A glycoprotein destined for secretion from the cell would move through the Golgi complex which sequence?
cis face to medial region to trans face
What happens during the cotransport of glucose and sodium ions?
glucose molecules are transported against their concentration gradiant
Proteins that are destined to become associated with the inner surface of the plasma membrane are
made on free ribosomes in the cytoplasm
The ratio of the size of the image seen with the microscope to the actual size of the object is called:
magnification
Which pair matches the correct macromolecule with the bond that joins its subunits?
nucleic acid ------ phosphodiester linkage
A single cell in a smoker's lung has become cancerous. It doubles its DNA and divides much faster than a normal lung cell. The most likely change that would have caused this condition took place in the:
nucleus
What process halts the net movement of water from a hypotonic solution into a plant's cells and often provides structural support to many plants?
turgor pressure
What is the microtubule arrangement of a flagellum or cilium?
9+2 arrangement
Why is it advantageous for cells to be small?
A small cell has a small volume relative to surface area, thereby increasing efficient transport
What is the difference between an electrically neutral atom and an ion?
An ion has an unequal number of protons and electrons, while a neutral atom has an equal number
DNA is associated with certain proteins, forming a complex called...
Chromatin
What are units of hereditary information?
Genes
What protects a cell and may help keep other cells at a distance?
Glycocalyx
What carbohydrate energy storage molecule is found in animal liver and muscle cells?
Glycogen
Which scenario best describes a double-blind study?
Neither the investigator or the subjects know if they are in the experimental or control group
Nitrogen has 5 electrons in its valence shell. How many electrons does it need to gain to complete its valence shell?
Three
What is the purpose of molecular chaperones?
To assist the folding of other molecular proteins
Which cellular structure is correctly matched to the role it plays within the cell?
centrosome--- cell division
What is found between the primary walls of adjacent cells to adhere tightly to one another?
middle lamella
In the experiment in which Frye and Edidin fused the plasma membranes of a mouse and a human cell, what happened to the membrane proteins?
they moved laterally across the cell surface
The role of ATP in the sodium-potassium pump is to:
transfer protons to the outside of a cell
What is the primary function of mitochondria?
transformation of energy
What represents the most basic level of chemical organization?
Atom
Which statement best summarizes the differences between RNA and DNA?
DNA compromises the genes, while RNA is a direct participant in the process of protein synthesis
Suppose a particular protein is produced in excess of the cell's needs. What kind of mechanism will intervene to stop production?
Homeostatic
The covalent bond between a hydrogen atom and the oxygen atom in water is formed when...
Hydrogen and oxygen share an electron pair
The representation H-O-H is known as a(n):
Structural formula
What is the purpose of a buffer?
To minimize the change in pH
A transmembrane protein differs from other membrane proteins because it
completely extends through the membrane