Chap 1: Evolution, Themes of Biology, & Scientific Theory (2)

Question 1

Explain the difference between chromosomes and genes.

Answer 1

• Chromosome is a DNA strand with part or all of the genetic material of an organism
• Each chromosome has one long DNA molecule with hundreds or thousands of genes

Question 1

The ability of cells to divide is the basis of which 3 processes?

Answer 1

1. Growth
2. Reproduction
3. Repair of multicellular organisms

Question 2

_______ control protein production indirectly. Explain.

Answer 2

Genes control protein production
indirectly.

Protein-encoding genes control protein production indirectly, using a related molecule called ribonucleic acid (RNA) as an intermediary.

Question 3

Define gene expression.

Answer 3

The transfer of information from a gene results in a functional protein.

Question 4

What is crystallin protein and how is it made?

Answer 4

The lens of the eye (behind
the pupil) can focus light because lens cells are tightly packed with transparent proteins called crystallin.

Question 5

Explain the process of gene expression.

Answer 5

1. The sequence of nucleotides along a gene is transcribed into RNA, which is then translated into a linked series of protein building blocks called amino
   acids.
2. Once completed, the amino acid chain forms a specific protein with a unique shape and function

Question 6

Differences among organisms reflect differences in their genetic codes. True or false?

Answer 6

False. Differences among organisms reflect differences among their nucleotide sequences rather than among their genetic codes

Question 7

Define genome.

Answer 7

The entire “library” of genetic instructions that an organism
inherits is called its genome.

Question 8

Define genomics and proteomics.

Answer 8

• Genomics is the study of sets of genes within and between species
• Proteomics is the study of all the proteins encoded by
  the genome (called proteomes

Question 9

What are the three important research developments that have made the genomic and proteomic approaches possible?

Answer 9

1. “high throughput” technology that can analyze many biological samples very rapidly.
2. The major development is
   bioinformatics, the use of computational tools to store,
   organize, and analyze the huge volume of data that results from high-throughput methods.
3. The third development is the formation of interdisciplinary research teams.

Question 10

Explain the energy flow in plants.

Answer 10

1. Light energy comes from the sun
2. Plants convert sunlight to
   chemical energy.
3. Plants take up chemicals from
   the soil and air.
4. Chemicals in plants are passed
   to organisms that eat the plants. Organisms use chemical energy to do work.

Question 11

How does energy enter and exit an ecosystem?

Answer 11

Energy flows through an ecosystem in one direction, usually entering as light and exiting as heat.

Question 12

Explain the regulation of blood sugar levels and name the mechanism.

Answer 12

Cells in the body must match the supply of fuel (sugar) to demand, regulating the opposing processes of sugar breakdown and storage.

The key is the ability of many biological processes to self regulate by a mechanism called
feedback.

Question 13

Define feedback regulation.

Answer 13

In feedback regulation, the output or product of a process regulates that very process.

Question 14

Define negative feedback and give example.

Answer 14

The most common form of regulation in living systems is negative feedback, a loop in which the response reduces the initial stimulus.

As seen in the example of insulin signaling.

Question 15

Explain the process of insulin signaling.

Answer 15

After a meal, the level of the sugar glucose in your blood rises, which stimulates cells of the pancreas to secrete insulin.

Insulin, in turn, causes body cells to take up glucose, thus decreasing blood glucose levels. This eliminates the stimulus for insulin secretion, shutting off the pathway.

Thus, the output of the process negatively regulates that process

Question 16

Define positive feedback.

Answer 16

Positive feedback: in which an end product speeds up its production.

ex: blood clotting.

Question 17

Explain blood clotting process.

Answer 17

When a blood vessel is damaged, structures in the blood called platelets begin to aggregate at the site.

Positive feedback occurs as chemicals released by the platelets attract more platelets.

The platelet pileup then initiates a complex process that seals the wound with a clot

Question 18

Global warming is not the only way the climate is changing. Explain.

Answer 18

Wind and precipitation patterns are also shifting, and extreme weather events such as storms
and droughts are occurring more often.

Question 19

What is the scientific explanation for the unity and diversity of
organisms?

Answer 19

The scientific explanation for the unity and diversity of organisms—as well as for the adaptation of organisms to their particular environments—is evolution: the concept that the organisms living on Earth today are the modified descendants of common ancestors.