DNA Flashcards
What makes up nucleic acids?
-DNA
-RNA
Nucleic acids function
Store and transmit the genetic instructions necessary for life to exist and reproduce itself
DNA functions/characteristics
-Deoxyribonucleic acid
-Contains the genetic instructions required for all single cell and multi cell life forms to develop, grow, renew, reproduce, defend, and respond to environmental conditions
-The long, polymeric nature of the DNA molecule enables it to store large quantities of genetic instructions
DNA structure
-Double helix
-Two complementary strands
-The Deoxyribonucleotide sequence of DNA determines the genetic instructions it stores
Each DNA strand consists of four types of chemical building blocks called
Nucleotides
Adenine, cytosine, guanine, thymine
The two strands of the helix are held together by what type of bond?
Hydrogen bond
Why do all single cell & multi cell species store their genetic instructions in DNA rather than RNA?
DNA is more stable than RNA
List reasons why DNA is more stable than RNA
-Stable double helix due to hydrogen bonding between the complementary base pairs
-Deoxyribonucleotides in DNA are more stable than ribonucleotides in RNA
-Complementary base pairing
What information is stored in the human genome?
-15 genes that code for DNA polymerases
-Consists of all the DNA molecules in the nucleus and the mitochondrion
Which monosaccharide is in every deoxyribonucleotide?
Deoxyribose
What gives DNA its negative electrical charge?
The phosphate group
Where is DNA located in human cells and other animal cells? In plant cells?
-Nucleus, mitochondrion
-Chloroplast
How many hydrogen bonds are formed between each complementary base pair?
-Adenine forms 2 hydrogen bonds with thymine
-Cytosine forms 3 hydrogen bonds with guanine
Which property of the double helix facilitates DNA replication and repair?
The rules of complementary base pairing
What is the sequence of the complementary DNA strand?
-The two strands must be in the opposite 5’ to 3’ orientation to interact
-Template (parent) strand: runs 3’ to 5’
-New strand: runs 5’ to 3’
-DNAP can only add nucleotides to the 3’ end of the growing strand
Why does the nucleus in your cells contain multiple DNA repair enzymes?
-There are ≥169 enzymes in the nucleus that participate in DNA repair
-DNA repair enzymes constantly scan DNA molecules to detect and correct mutations
-Synthesize DNA (DNAP)
-Synthesize deoxyribonucleotides (A, C, G, T)
-Repair mutations in DNA
Why do some women take folic acid supplements before and during pregnancy?
-Folic acid (vitamin B9 - water soluble) is required to make thymine for DNA synthesis
-Folic acid deficiency may result in abnormal human development (spina bifida, anencephaly)
The nucleotide sequences of DNA molecules store a variety of instructions:
-Make every protein required by cells
-Make every specialized RNA molecule required by cells
-Regulate the activation/deactivation of all genes
-Replicate all DNA molecules
-Position all DNA molecules correctly in the nucleus
-Protect the ends of linear DNA molecules
-Ensure that DNA molecules are accurately distributed during cell division
Phosphate group charge
Negative
What atom makes deoxyribose more stable than ribose
Hydrogen atom
Pyrimidines
-1 ring
-Cytosine (DNA, RNA)
-Thymine (DNA)
-Uracil (RNA)
Purines
-2 fused chemical rings
-Adenine (DNA, RNA)
-Guanine (DNA, RNA)
How are DNA molecules synthesized?
DNA polymerases link the deoxyribonucleotides together in a precise order
-Follow the rules of complementary base pairing
DNAP enzymes
Have a proofreading ability that enables them to correct their mistakes
