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DNA (Chapter 12)

Terms in this set (28)

DNA
deoxyribonucleic acid
nucleotides
molecules that make up DNA
types of nucleotides
deoxyribose, phosphate group & nitrogen base
nitrogen bases
adenine (A), thymine (T), guanine (G) & cytosine (C)
base pairing
when hydrogen bonds can only form between certain nitrogen base pairs: A-T & G-C or T-A & C-T
double helix
two strands of nucleotides wrapped around each other (twisted ladder)
DNA replication
1) The enzyme helicase separates the two strands of DNA.
2) DNA polymerase produces two new strands following the rules of nitrogen base pairing.
3) Each double helix of DNA serves as a model for a new strand (1/2 old & 1/2 new)
chromosomes
are made of DNA
proteins
code the segments of DNA and relate to a trait (eye color, enzymes, hormones, etc.) DNA --> Protein --> Traits
RNA
ribonucleic acid
RNA
1) single-stranded (one side)
2) uracil base instead of thymine base (U-A not T-A)
3) sugar ribose instead of deoxyribose
transcription
an mRNA copy is made from the DNA (a mold)
translation
the mRNA strand is read and amino acids are linked together to form a protein
mutation
a change in genetic material (good or bad)
mutagen
something that can increase the frequency of mutation
ex: chemicals/radiation (Chernobyl)
carcinogen
any substance or agent that tends to produce a cancer
ex: Asbestos, DDT or tobacco
point mutations
mutations involving only one or a few nucleotides: sustitution, insertion and deletion
substitution
mutation involving 1 switched nucleotide
insertion
mutation involving 1 added nucleotide
deletion
mutation involving 1 removed nucleotide/chromosome
frameshift mutations
change or shift whole genetic message by inserting or deleting a nucleotide; can effect every amino acid by a chain of RNA & make a protein unable to do its job
chormosomal mutations
change in the number or structure of chromosomes: deletion, duplication, inversion and translocation
duplication
mutation involving an extra chromosome
inversion
mutation involving reverse chromosome
translocation
mutation involving parts of one chromosome sticking together
sex-linked genes
genes located on the X & Y chromosome
ex: color-blindness & normal vision
genetic disorders
sickle cell disease: bent and twisted shape of red blood cells - pointed mutation
cystic fibrosis: caused by a recessive allele on chromosome 7
codon
three nucleotides brought together in mRNA to code for an amino acid
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