Bio 110 HW #1 Tutorials 1-3

an organism that dies after five days of life but leaves 10 offspring, all of whom survive to reproduce

four other water molecules by hydrogen bonds

polar - The electrons spend more time with the oxygen of the water molecule than with the hydrogens of water. Thus, the oxygen has a net negative charge and the hydrogens have a net positive charge.

electronegativity

polar covalent - While oxygen shares electrons with hydrogen, the electrons spend more time with the oxygen than with the hydrogens.

surface tension - The high surface tension of water allows the insect to remain on the surface.

water's high heat of vaporization - Evaporative cooling takes place when molecules with the greatest kinetic energy leave a fluid as gas molecules. Because of water's high heat of vaporization, a large amount of heat must be absorbed for 1 gram of water to be converted from liquid to gas. The dog loses this heat as the water on its tongue evaporates, allowing him to cool down by panting. To understand why this answer is correct, read about evaporative cooling.

adhesion of water molecules to other kinds of molecules - Water adheres to the cellulose molecules in a paper towel, allowing the towel to pick up a puddle of water. This is similar to the adhesion between water molecules and cellulose in cell walls responsible for water transport in plants.

water's high surface tension - Water's high surface tension, related to its cohesion, makes water behave as though coated with an invisible film.

Carbon - With four electrons to share, carbon-based molecules can be multibranching and three-dimensionally variable.

proteins - Proteins are composed of amino acids joined together.

an oxygen The central carbon atom in an amino acid is bonded to: - an amino functional group - a carboxyl functional group - a side chain (R group) - hydrogen

carboxyl functional group - The carboxyl group (COOH) contains two oxygen atoms that tend to pull electrons away from the hydrogen atom, so this group tends to lose a proton and is acidic.

nucleotides - Nucleotide monomers make up nucleic acids.

A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid. A hydroxyl group is removed from the carboxyl group of one amino acid and hydrogen is removed from the amino group of the other amino acid, allowing a bond to form between the two groups.

True - Enzymes in the digestive tract break down food molecules, which is a process that occurs by hydrolysis.

C2H4

The fossil record presents an incomplete picture of the history of life because all species are not equally likely to leave fossils. Hard-shelled species that die where sediment is actively being deposited are most likely to fossilize, whereas soft-bodied species that die where they cannot be buried are rarely fossilized. Moreover, if a species is not abundant or does not exist for a long time, its fossils will likely be rare. Species that die in an environment with a low oxygen content are more likely to leave fossils because a low oxygen content inhibits decomposition.

22,900 years old

4

3.5 billion years ago

Neanderthals and modern humans may have lived in the same region for up to approximately 2,000 years, or they may not have overlapped at all.

No, the 14C present in the dinosaur when it died would decay too much to be measured after 65.5 million years.

Yes, after 65.5 million years only about one tenth of the 235U would have decayed, leaving plenty to measure in the fossils.