DNA, RNA, DNA replication

function of DNA

hereditary information

primary long-term storage molecule for genetic information in all living organisms

structure of DNA

double helix

(phosphate backbone and nitrogen bases)

what does DNA stand for

deoxyribose nucleic acid

monomer

small, basic molecules that act as a building block to form long, complex chains called polymers

nucleotide

makes up DNA, part of the double helix

complementary pairing

specific, consistent matches of nitrogenous bases

base pairings

Adenine – Thymine, Cytosine – Guanine

what bonds are base pairings joined by

hydrogen bonds

difference between DNA and RNA

DNA, RNA

1. Double-stranded // single-stranded

2. deoxyribose sugar // ribose sugar molecules

3. A T C G bases // A, Uracil, C G bases

4. nucleus, mitochondria // nucleolus, cytoplasm

5. blueprint for life // converts genetics to proteins

the protein DNA is wrapped in

histone

genome

entire set of DNA

chromsome

tightly coiled package of DNA

carried information about the organism in units of genes

gene

specific segment of DNA

how many chromosomes in human body

46 chromosomes in 23 homologous pairs

homologous pairs

same size, shape, and carry the same genes at same positions (loci), may have different alleles

sex chromosomes

determines the sex of an individual

autosomes

not sex chromosomes

diploid

two complete sets of chromosomes– one from mum, one from dad

haploid

one single set of chromosomes

karyotyping

a profile of all the chromosomes in the nucleus of an organism’s single cell

• prepared from nuclei of cultured WBC

• frozen at metaphase

trisomy

an extra chromosome

trisomy 13

patau syndrome

trisomy 18

edwards syndrome

trisomy 21

down syndrome

XXY

klinefelter syndrome

X0

turners syndrome

XYY syndrome

XYY syndrome

why does DNA replication need to occur?

so that there is enough DNA for all cells in mitosis / meiosis

semi-conservative

each strand acts as a template for the synthesis for a new, complementary strand