Genes and Proteins
Key Terms
Investigations 1 and 2
1. DNA- (Deoxyribonucleic Acid) nucleic acid that carries genetic information in cells and
consists of two complementary chains of nucleotides wound in a double helix held together by
hydrogen bonds. Contains a deoxyribose sugar and four nitrogen bases- cytosine, thymine,
adenine, and guanine
2. RNA-(Ribonucleic Acid) group of single-stranded nucleic acids, including mRNA
(messenger RNA), that is necessary for transcription and translation. Contains a ribose sugar and
three of the same nitrogen bases as DNA cytosine, adenine, and guanine and a fourth only found
in RNA uracil.
3. Codon- three adjacent nucleotides in DNA or mRNA that code for a specific amino acid in a
protein
4. Stop Codon- signal the cell to stop adding amino acids to the protein
5. Protein- large molecule consisting of one or more chains of amino acids (polypeptides);
polymers of amino acids
6. Amino Acid- building blocks of protein molecules also called polypeptides
7. DNA Replication- process by which copies of DNA are made
8. Genes- made up of DNA, each gene encodes for one protein
9. Transcription- transcription occurs in the nucleus of a cell; DNA is used as a template to be
transcribed into RNA
10. Translation- occurs in a ribosome; the information in RNA is translated into a protein
(polypeptide)
11. Mutation- A change in the DNA sequence of a gene
12. Wild-Type Protein- a protein that is produce when there are no mutations
13. Substitution- one nucleotide is changed into a different nucleotide
14. Insertion- one or more nucleotides is inserted into the DNA sequence
15. Deletion- one or more nucleotides is removed from the DNA sequence
Investigation 3
19. Chromosome- structures of DNA and protein in the nucleus of cells, where genes are
located
20. Homologous Chromosomes- each body cell has two copies of chromosomes in its nucleus.
21. Interphase- first part of the cell cycle, cells grow large and the chromosomes are duplicated
22. Sister Chromatids- two identical copies of each chromosome, they are attached by a
structure called the centromere
23. Mitosis- second part of the cell cycle; cell division, characterized by chromosome replication
and formation of two identical daughter cells. There are four phases of mitosis
PMAT- (Prophase, Metaphase, Anaphase, and Telophase)
24. Prophase- first phase of mitosis, the nuclear membrane dissolves; chromosome condense
into rod-like structure
25. Metaphase- second phase of mitosis, spindle fibers have formed in the cell, chromosomes
line up as pairs of duplicated homologous chromosomes in the center of the cell
26 Anaphase- third phase of mitosis; chromatids separate and move down the spindle fibers to
opposite ends of the cell
27. Telophase- fourth phase of mitosis; the chromatids have moved to the ends of the spindle
fibers and the fibers disappear. Nuclear membranes form around each set of chromosomes and
the cell is prepared to divide.
28. Somatic or Body cells- one of two types of cells in the human body, these cells are cells in
the skin, stomach, muscles, and other organs, they divide through mitosis
29. Gametes or sex cells- responsible for passing on genetic information to the next generation
through a process called meiosis.