Chapter 3

Question 1

Homeostasis

Answer 1

A steady internal condition maintained by responses that compensate for changes in the external environment

Question 2

Biotic

Answer 2

Biological. Often in reference to living component of the environment.

Question 3

Abiotic

Answer 3

Nonbiological. Often in reference to physical factors in the environment.

Question 4

Emergent properties

Answer 4

What we see as life is the result of atomic interactions and physical processes

Question 5

Habitable zone

Answer 5

The specific environment in which a population lives, as characterized by its Biotic and Abiotic factors.

Question 6

Nucleic acids

Answer 6

a complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain.

Question 7

Proteins

Answer 7

Molecules that carry out most of the activities of life, including the synthesis of all other biological molecules. A protein consists of one or more polypeptides depending on the protein.

Question 8

Lipids

Answer 8

any of a class of organic compounds that are fatty acids or their derivatives and are insoluble in water but soluble in organic solvents. They include many natural oils, waxes, and steroids.

Question 9

Carbohydrates

Answer 9

any of a large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body.

Question 10

Ozone

Answer 10

a colorless unstable toxic gas with a pungent odor and powerful oxidizing properties, formed from oxygen by electrical discharges or ultraviolet light. It differs from normal oxygen (O2) in having three atoms in its molecule (O3).

Question 11

Polymer

Answer 11

a substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together

Question 12

Monomer

Answer 12

Identical or nearly identical subunits that link together to form polymers during polymerization

Question 13

Enzyme

Answer 13

Proteins that accelerates the rate of a cellular reaction

Question 14

Protobiont

Answer 14

The term given to a group of abiotically produced organic molecules that are surrounded by a membrane or membrane-like structure

Question 15

Liposome

Answer 15

a minute spherical sac of phospholipid molecules enclosing a water droplet, especially as formed artificially to carry drugs or other substances into the tissues.

Question 16

DNA

Answer 16

The large, double-stranded, helical molecule that contains the genetic material of all living organisms

Question 17

RNA

Answer 17

A polymer assembled from repeating nucleotide monomers in which the five-carbon sugar is ribose. Cellular RNAs are mRNA (which is translated to produce a polypeptide). tRNA (which brings an amino acid to the ribosome for assembly into a polypeptide during translation), and rRNA (which is a structural component of ribosomes). The genetic material of some viruses is RNA.

Question 18

Transcription

Answer 18

The mechanism by which the information encoded in DNA is made into a complementary RNA copy

Question 19

Translation

Answer 19

The use of information encoded in the RNA to assemble amino acids into a polypeptide.

Question 20

Ribozymes

Answer 20

An RNA-based catalyst that is part of the biochemical machinery of cells

Question 21

Metabolism

Answer 21

The biochemical reactions that allows a cell or organism to extract energy from its surroundings and use that energy to maintain itself, grow, and reproduce.

Question 22

Oxidize

Answer 22

Substances from which the electrons are removed during oxidization

Question 23

Reduce

Answer 23

Substance that receives energy during reduction

Question 24

Stromatolites

Answer 24

Fossilized remains of ancient cyanobacterial mats that carries out photosynthesis by the water-splitting reaction

Question 25

Autotroph

Answer 25

An organism that produces its own food using CO2 and other simple inorganic compounds from its environment and energy from the sun or from oxidation of inorganic substances.

Question 26

Phototroph

Answer 26

An organism, typically a plant, obtaining energy from sunlight as its source of energy to convert inorganic materials into organic materials for use in cellular functions such as biosynthesis and respiration.

Question 27

Panspermia

Answer 27

the theory that life on the earth originated from microorganisms or chemical precursors of life present in outer space and able to initiate life on reaching a suitable environment.

Question 28

Extremeophile

Answer 28

a microorganism, especially an archaean, that lives in conditions of extreme temperature, acidity, alkalinity, or chemical concentration.

Question 29

Astrobiology

Answer 29

the branch of biology concerned with the study of life on earth and in space

Question 30

Domain

Answer 30

In protein structure, a distinct, large, structural subdivision produced in many proteins by the folding of the amino acid chain. In systematics, the highest taxonomic category; a group of cellular organisms with characteristics that set it apart as a major branch of the evolutionary tree.

Question 31

LUCA

Answer 31

The last universal common ancestor (LUCA) is the name given to a crude organism that is now traceable in all domains of life; plants, animals, fungi, algae, etc.

Question 32

Endosymbiosis

Answer 32

Based on a number of observations scientists proposed that chloroplasts and mitochondria originated as bacteria.

Question 33

Genome

Answer 33

The entire collection of DNA sequence for a give organism

Question 34

Horizontal gene transfer

Answer 34

Horizontal gene transfer (HGT) refers to the transfer of genes between organisms in a manner other than traditional reproduction. Also termed lateral gene transfer (LGT), it contrasts with vertical transfer, the transmission of genes from the parental generation to offspring via sexual or asexual reproduction.

Question 35

Endomembrane system

Answer 35

In eukaryotes, a collection of interrelated internal membranous sacs that divide a cell into functional and structural compartments