Science test Flashcards-study guide

Question 1

cytosine

Answer 1

a compound found in living tissue as a constituent base of nucleic acids. It is paired with guanine in double-stranded DNA.

Question 2

adenine

Answer 2

a compound which is one of the four constituent bases of nucleic acids. A purine derivative, it is paired with thymine in double-stranded DNA.

Question 3

guanine

Answer 3

a compound that occurs in guano and fish scales, and is one of the four constituent bases of nucleic acids. A purine derivative, it is paired with cytosine in double-stranded DNA.

Question 4

thymine

Answer 4

a compound which is one of the four constituent bases of nucleic acids. A pyrimidine derivative, it is paired with adenine in double-stranded DNA.

Question 5

deoxyribose

Answer 5

a sugar derived from ribose by replacing a hydroxyl group with hydrogen.

Question 6

phosphate

Answer 6

a salt or ester of phosphoric acid, containing PO43− or a related anion or a group such as —OPO(OH)2.

Question 7

hydrogen bond

Answer 7

Hydrogen bonding is a special type of dipole-dipole attraction between molecules, not a covalent bond to a hydrogen atom.

Question 8

nitrogenous base

Answer 8

Nitrogenous base: A molecule that contains nitrogen and has the chemical properties of a base.

Question 9

nucleotide

Answer 9

A nucleotide is the basic building block of nucleic acids (RNA and DNA). A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base.

Question 10

pedigree

Answer 10

A diagram of family history that uses standardized symbols.

Question 11

heredity

Answer 11

the passing on of physical or mental characteristics genetically from one generation to another.

Question 12

trait

Answer 12

a distinguishing quality or characteristic, typically one belonging to a person.

Question 13

genetics

Answer 13

Genetics is the scientific study of genes and heredity—of how certain qualities or traits are passed from parents to offspring as a result of changes in DNA sequence.

Question 14

fertilization

Answer 14

fertilization

Question 15

purebred

Answer 15

(of an animal) bred from parents of the same breed or variety.

Question 16

gene

Answer 16

(in informal use) a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

Question 17

alleles

Answer 17

one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Question 18

dominant allele

Answer 18

A dominant allele is a variation of a gene that will produce a certain phenotype, even in the presence of other alleles.

Question 19

recessive allele

Answer 19

Recessive refers to a type of allele which will not be manifested in an individual unless both of the individual’s copies of that gene have that particular genotype.

Question 20

hybrid

Answer 20

the offspring of two plants or animals of different species or varieties, such as a mule (a hybrid of a donkey and a horse).

Question 21

probability

Answer 21

the extent to which something is probable; the likelihood of something happening or being the case.

Question 22

Punnett square

Answer 22

The Punnett square is a square diagram that is used to predict the genotypes of a particular cross or breeding experiment.

Question 23

phenotype

Answer 23

the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Question 24

genotype

Answer 24

the genetic constitution of an individual organism.

Question 25

homozygous

Answer 25

having two identical alleles of a particular gene or genes.

Question 26

heterozygous

Answer 26

having two different alleles of a particular gene or genes.