Anthr 3 4

Front 1

amino acids

Back 1

Small molecules that are the components of proteins.

Front 2

autosomes

Back 2

All chromosomes except the sex chromosomes.

Front 3

centromere

Back 3

The constricted portion of a chromosome. After replication, the two strands of a double-stranded chromosome are joined at the centromere.

Front 4

chromosomes

Back 4

Discrete structures composed of DNA and protein found only in the nuclei of cells. Chromosomes are only visible under magnification during certain phases of cell division.

Front 5

clone

Back 5

An organism that is genetically identical to another organism. The term may also be used to refer to genetically identical DNA segments and molecules.

Front 6

codon

Back 6

A triplet of messenger RNA bases that refers to a specific amino acid during protein synthesis.

Front 7

complementary

Back 7

Referring to the fact that DNA bases form base pairs in a precise manner. For example, adenine can bond only to thymine. These two bases are said to be complementary because one requires the other to form a complete DNA base pair.

Front 8

cytoplasm

Back 8

The portion of the cell contained within the cell membrane, excluding the nucleus. The cytoplasm consists of a semifluid material and contains numerous structures involved with cell function.

Front 9

enzymes

Back 9

Specialized proteins that initiate and direct chemical reactions in the body.

Front 10

gametes

Back 10

Reproductive cells (eggs and sperm in animals) developed from precursor cells in ovaries and testes.

Front 11

gene

Back 11

A sequence of DNA bases that specifies the order of amino acids in an entire protein, a portion of a protein, or any functional product. A gene may be made up of hundreds or thousands of DNA bases organized into coding and noncoding segments.

Front 12

genome

Back 12

The entire genetic makeup of an individual or species. In humans, it is estimated that each individual possesses approximately 3 billion DNA nucleotides.

Front 13

Hemoglobin

Back 13

A protein molecule that occurs in red blood cells and binds to oxygen molecules.

Front 14

homeotic genes

Back 14

An evolutionarily ancient family of regulatory genes that direct the development of the overall body plan and the segmentation of body tissues; also called homeobox or Hox genes.

Front 15

homologous

Back 15

Referring to members of chromosome pairs. Homologous chromosomes carry loci that govern the same traits. During meiosis, homologous chromosomes pair and exchange segments of DNA. They are alike with regard to size, position of centromere, and banding pattern.

Front 16

hormones

Back 16

Substances (usually proteins) that are produced by specialized cells and that travel to other parts of the body, where they influence chemical reactions and regulate various cellular functions.

Front 17

Human Genome Project

Back 17

An international effort aimed at sequencing and mapping the entire human genome.

Front 18

meiosis

Back 18

Cell division in specialized cells in ovaries and testes. Meiosis involves two divisions and results in four daughter cells, each containing only half the original number of chromosomes. These cells can develop into gametes.

Front 19

messenger RNA (mRNA)

Back 19

A form of RNA that is assembled on a sequence of DNA bases. It carries the DNA code to the ribosome during protein synthesis.

Front 20

mitochondrial DNA (mtDNA)

Back 20

DNA found in the mitochondria that is inherited only from the mother.

Front 21

mitosis

Back 21

Simple cell division; the process by which somatic cells divide to produce two identical daughter cells.

Front 22

molecules

Back 22

Structures made up of two or more atoms. Molecules can combine with other molecules to form more complex structures.

Front 23

nondisjunction

Back 23

The failure of homologous chromosomes or chromosome strands to separate during cell division.

Front 24

nucleotides

Back 24

Basic units of the DNA molecule, composed of a sugar, a phosphate, and one of four DNA bases.

Front 25

nucleus

Back 25

A structure (organelle) found in all eukaryotic cells. The nucleus contains chromosomes (nuclear DNA).

Front 26

organelles

Back 26

Structures contained within cells, surrounded by a membrane. There are many different types, and each performs specific functions.

Front 27

polymerase chain reaction (PCR)

Back 27

A method of producing thousands of copies of a DNA segment using the enzyme DNA polymerase.

Front 28

protein synthesis

Back 28

The assembly of chains of amino acids into functional protein molecules. The process is directed by DNA.

Front 29

proteins

Back 29

Three-dimensional molecules that serve a wide variety of functions through their ability to bind to other molecules.

Front 30

recombinant DNA technology

Back 30

A process in which genes from the cell of one species are transferred to somatic cells or gametes of another species.

Front 31

recombination

Back 31

The exchange of genetic material between homologous chromosomes during meiosis.

Front 32

replicate

Back 32

To duplicate. The DNA molecule is able to make copies of itself.

Front 33

ribonucleic acid (RNA)

Back 33

A single-stranded molecule, similar in structure to DNA. Three forms of RNA are essential to protein synthesis. They are messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).

Front 34

ribosomes

Back 34

Structures composed of a form of RNA called ribosomal RNA (rRNA) and protein. Ribosomes are found in the cell’s cytoplasm and are essential to the manufacture of proteins.

Front 35

sex chromosomes

Back 35

In mammals, the X and Y chromosomes.

Front 36

somatic cells

Back 36

Basically, all the cells in the body except those involved with reproduction.

Front 37

transfer RNA (tRNA)

Back 37

The type of RNA that binds to specific amino acids and transports them to the ribosome during protein synthesis.

Front 38

zygote

Back 38

A cell formed by the union of an egg and a sperm cell. It contains the full complement of chromosomes (in humans, 46) and has the potential of developing into an entire organism.