bio chapter 2
Glucose (a monosaccharide) has the molecular formula C6H12O6. How many carbon atoms are in each glucose molecule?
6
What is the relationship between acids (acidic solutions), bases (basic solutions), and hydroxide ions?
Acids contain relatively few hydroxide ions, whereas bases contain excess hydroxide ions.
Which of the following gives researchers hope that life may exist on Mars? Evidence that liquid water may still exist on Mars. Versions of life may come in a form that does not contain all the hallmarks of life, such as viruses. Seasonal patterns of methane emissions have been detected that are similar to patterns created on earth by biological organisms. All of the answers are correct. Life on Earth survives in extreme conditions
All of the answers are correct.
What makes ice less dense than liquid water?
Hydrogen bonds between the water molecules in the crystal of ice expand its volume (atoms occupy a larger volume) making it less dense than water (liquid).
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 ice bergs
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.
Why is the phospholipid bilayer important to cell survival? Select the TWO answers that are correct. It blocks small, nonpolar molecules from entering the cell and harming it. It anchors nucleotides together as they form molecules of DNA. It maintains homeostasis by forming an insulating layer around the cell. It acts as a barrier for some, but not all, molecules on either side of it. 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. It separates the cellular environment from the external environment.
When an atom loses an electron, what happens?
It becomes positively charged.
How do triglycerides and phospholipids differ? Select the TWO answers that are correct. Phospholipids have ribose in place of the deoxyribose used in triglycerides. Phospholipids are saturated with hydrogens, whereas triglycerides are unsaturated. Phospholipids have two fatty acid tails, whereas triglycerides have three. Phospholipids store energy, whereas triglycerides are cell membrane components. Phospholipids have a hydrophilic phosphate group in place of one fatty acid tail.
Phospholipids have two fatty acid tails, whereas triglycerides have three. Phospholipids have a hydrophilic phosphate group in place of one fatty acid tail.
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.
How do RNA and DNA molecules differ? Select the TWO answers that are correct. RNA molecules contain sugars in its backbone, whereas DNA molecules do not. Adenine is present in RNA molecules, whereas cytosine is present only in DNA molecules. RNA molecules are single-stranded most of the time, whereas DNA molecules are almost always double-stranded. Uracil is present in RNA molecules, whereas thymine is present only in DNA molecules. RNA molecules have one fatty acid chain, whereas DNA molecules have two of them.
RNA molecules are single-stranded most of the time, whereas DNA molecules are almost always double-stranded. Uracil is present in RNA molecules, whereas thymine is present only in DNA molecules.
Which of the following statements about carbon is FALSE?
Soil samples containing carbon must contain life
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.
How does water dissolve table salt?
Water is a polar molecule that disrupts ionic bonds between sodium and chloride.
What characteristics define an organic molecule? Select the TWO correct answers. a carbon-nitrogen bond a carbon backbone (at least one carbon) a carbon-hydrogen bond a carbon-oxygen bond presence of nitrogen
a carbon backbone (at least one carbon) a carbon-hydrogen bond
Which of the following are most likely to dissolve in olive oil?
a nonpolar molecule
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
A cell is unable to take up or make sugars. Which molecules will it be unable to take up or make?
carbohydrates and nucleic acids
As an acidic compound dissolves in water, the pH of the water _______.
decreases
Which substances have an alkaline pH? Select the TWO answers that are correct. battery acid drain cleaner coffee baking soda orange juice
drain cleaner baking soda
Which part of an atom forms covalent bonds with other atoms?
electrons in the outermost energy shell
Which part of the cell membrane acts as a barrier to hydrophilic molecules entering the cell?
hydrophobic tails
What are the four types of organic molecules that make up all living things on Earth?
lipids, nucleic acids, carbohydrates, proteins
What determines the identity of a particular atom? Select the correct answer
number of protons in the nucleus
Which of the characteristics of life does a virus display, even though its characterization as being alive is controversial?
the ability to reproduce and grow