Biology Animation Quiz Ch. 1-4

What makes ice less dense than liquid water?

Hydrogen bonds between water molecules expand when solid.

What is the relationship between acids, bases, and hydroxide ions?

Acids contain relatively few hydroxide ions, whereas bases contain excess hydroxide ions.

Why are chloroplasts essential to the survival of many animals as well as plants?

Animals do not have chloroplasts and must depend on organisms that can photosynthesize the energy they need.

How does the cell wall protect prokaryotic cells in a hypotonic solution?

Because cells swell in a hypotonic environment, the bacterial cell wall counteracts the outward osmotic pressure and prevents the cell from bursting.

What did the researchers conclude from the experiment about how cell phone radiation affects the incidence of cancer?

Cell phone radiation increases the likelihood of certain cancers in male rats.

Which statement describes a correlation between two variables?

Correlated variables are interdependent; as one varies so does the other in a predictable fashion.

Why are eukaryotic cells unaffected by streptomycinand similar antibiotics?

Eukaryotic protein synthesis is not disrupted because these antibiotics do not disrupt eukaryotic ribosomal activity.

Polar bears rely on Arctic ice sheets and icebergs on the surface of water as a part of their habitat. How would the habitat of polar bears be affected if solid water was more dense than liquid water?

Ice would sink rather than float, so there would be no ice sheets or icebergs.

Why do salt crystals form in a pan of seawater from which the water has been evaporated?

In the absence of water, sodium and chloride form ionic bonds and aggregate into crystals.

How does an enzyme affect the activation energy of a reaction?

It reduces the energy of activation, which makes the reaction it facilitates more likely to occur and speeds up the production of the chemical product.

Why is sample size important?

Larger sample size increases the likelihood that the results of a study are not due to random chance.

How does the DNA of prokaryotic cells differ from the DNA of eukaryotic cells?

Prokaryotic DNA is contained in the cytoplasm, whereas eukaryotic DNA is contained in the nucleus.

Where are the protons, neutrons, and electrons located in an atom?

Protons and neutrons are located in the nucleus, and electrons are located in orbitals.

Which example describes the set-up of a controlled experiment?

Ten subjects receive a new drug and another ten subjects receive a sugar pill.

Why is the phospholipid bilayer considered semipermeable?

The bilayer is a barrier to some, but not all, substances on either side of it.

How does the molecular structure of a water molecule affect its polarity?

The oxygen has a partial negative charge and the hydrogens have a partial positive charge, yielding a weakly polar water molecule that can form hydrogen bonds.

Why do some enzymes need a cofactor in order to function?

The presence of a cofactor allows some enzymes to bind to their substrates.

How do penicillin and similar antibiotics affect prokaryotic cells?

These antibiotics disrupt the formation of the cell wall so it cannot counteract osmotic pressure in a hypotonic environment, resulting in cell lysis.

How do streptomycin and similar antibiotics affect prokaryotic cells?

These antibiotics interfere with protein synthesis.

Why are nucleic acids considered macromolecules but not macronutrients?

They can be assembled into large molecules, but organisms need only small quantities of them in the diet.

What must happen to macromolecules before they can be absorbed by the body?

They must be digested into their constituent subunits.

How does water dissolve table salt?

Water is a polar molecule that disrupts ionic bonds between sodium and chloride.

Which statement describes a hydrogen bond between two water molecules?

a weak bond between the slightly negative oxygen atom of one water molecule and the slightly positive hydrogen atoms of another water molecule

Which part of an atom forms covalent bonds with other atoms?

electrons in the outermost energy shell

Which trait is NOT a functional characteristic of all living things?

protect self from predators

Anna is majoring in public health. She is designing an epidemiological study to examine the relationship between alcohol consumption and academic performance at her university. In addition to ensuring that she has a large enough sample size, what strategy should she take to make sure her conclusions are accurate?

randomly survey a group of participants that are representative of the general student body

What is activation energy?

the energy necessary to initiate a chemical reaction

Which statements describe catabolic and anabolic reactions? Select the TWO answers that are correct.

~Anabolic reactions add chemical bonds and result in smaller molecules being built up into larger ones. ~Catabolic reactions remove chemical bonds and result in larger substances being broken down into smaller ones.

Which statements describe cofactors and coenzymes? Select the TWO answers that are correct.

~Cofactors and coenzymes both facilitate the binding of enzymes to substrates. ~Cofactors can be organic or inorganic molecules, whereas coenzymes are only organic.

Which statements describe the relationship between correlation and causation? Select the TWO that are correct.

~Correlation alone is not sufficient evidence to attribute causation. ~Either variable might be the cause, or both variables might be influenced by a third unknown variable.

How does the shape of an enzyme affect its function? Select the TWO answers that are correct.

~Enzyme shape determines what substrate the active site can bind. ~When an enzyme binds a substrate, the enzyme's shape changes to facilitate a chemical reaction.

Why is the phospholipid bilayer important to cell survival? Select the TWO answers that are correct.

~It separates the cellular environment from the external environment. ~It acts as a barrier for some, but not all, molecules on either side of it.

Using the same independent and dependent variables as in the first experiment, researchers could extend the studies to test which of the following hypotheses? Select the TWO answers that are correct.

~Low intensity, long duration exposure to radiation has a greater influence on the incidence of cancer than high intensity. ~The incidence of cancer increases with increased levels of cell phone radiation.

How do triglycerides and phospholipids differ? Select the TWO answers that are correct.

~Phospholipids have two fatty acid tails, whereas triglycerides have three, ~Phospholipids have a hydrophilic phosphate group in place of one fatty acid tail.

How are eukaryotic cells different from prokaryotic cells? Select the TWO answers that are correct.

~Prokaryotic cells are generally smaller than eukaryotic cells. ~Eukaryotic cells have organelles, whereas prokaryotic cells do not.

Which statements describe the structure of the cell membrane? Select the TWO answers that are correct.

~The cell membrane is composed of a bilayer of phospholipids, each of which contains a hydrophilic head and a hydrophobic tail. ~The hydrophilic head interacts with the external environment or the cytoplasm, and the hydrophobic tail interacts with other phospholipid tails within the cell membrane.

What characteristics does a scientific hypothesis have? Select the TWO answers that are correct.

~The hypothesis is something that can be tested . ~The hypothesis could be proven false.

How do RNA and DNA molecules differ? Select the TWO answers that are correct.

~Uracil is used in RNA, whereas thymine is used in DNA. ~RNA is single-stranded, whereas DNA is double-stranded.

What characteristics make a particular molecule organic? Select the TWO answers that are correct.

~a carbon backbone ~a carbon-hydrogen bond

Which substances have an alkaline pH? Select the TWO answers that are correct.

~baking soda ~drain cleaner

Which tasks do water vacuoles and cell walls both perform in plant cells? Select the TWO answers that are correct.

~keep plant upright ~maintain cell shape

One argument explaining why viruses are not living is that viruses depend on the cells of other living creatures in order to multiply. Which characteristics of life does this argument use? Select the TWO answers that are correct.

~reproduction ~growth

What determines the identity of a particular atom? Select the TWO answers that are correct.

~total number of electrons in orbitals ~number of protons and number of neutrons in the nucleus

What functions do membrane proteins serve?

~transport nutrients into the cell that cannot otherwise cross the phospholipid bilayer ~transport wastes out of the cell that cannot otherwise cross the cell membrane