Nucleic acids and the cell cycle

3 characteristics of dna

helical, double stranded, anti parallel

how are two dna strands joined together

through base pairings of nucleotides and hydrogen bonds

antiparallel

paralell, except they run in opposite directions

3 components of a nucleotide

phosphate group, pentose sugar (5 carbon), and nitrogen containing base

sugar molecule in dna

deoxyribose (always contains 1 less oxygen)

sugar molecule in rna

ribose

nitrogen containing bases in dna

thymine, adenine, guanine, cytosine

nitrogen containing bases in rna

uracil, adeninem guanine, cytosine

complimentary base pairing

pairing of the nitrogenous base and one strand of dna with the base of another

complimentary base pairings in dna

adenine with thymine, guanine with cytosine

complimentary base pairing in rna

adenine with uracil, guanine with cytosine

purines

double ring nitrogen bases: adenine and guanine

pyramidines

signle ring nitrogen bases: cytosine, uracil, thymine

what makes up the backbone of a dna/rna strand

pentose sugar and phosphate groups - phosphate group always links to the 3rd carbon of one sugar and the 5th of another

what makes up the inside of a dna/rna strand

nitrogenous bases bonded together via hydrogen bonds

similarities of dna and rna

both made up of nucleotides, both twisted

differences in # of strands between dna and rna

dna is double stranded, rna is single stranded

dna’s function

to be coded to rna

rna’s function

to be coded into protiens

function of nucleic acids

contains codes (Nitrogen bases varying in sequence) determining characteristics of organisms

rna

an in between molecule of dna that passes the code along so protiens can be synthesized in ribosomes

chromatin

uncondensed genetic material that is a long, thin tangled mass of fibers

chromosomes

condesned chromatin packaged into linear bundles

centriole

a cell organelle composed of protien microtubules that produces spindle fibers

spindle fibres

a fibre composed of microtubules that attatch to chromosomes at the centromere region and move chromosomes around the cell

nuclear membrane

membrane surrounding genetic material to form the nucleus, seperating it from the rest of the cell

centromere

region of the chromosome where sister chromatids are joined

chromatid

an identical copy of a chromosome when joinedthe

the cell cycle

process of cell replicating through of asexual reproduction

interphase

where the cell undergoes most of its growth and metoblism processes

G1

growth 1, all organelles and cell contents except for dna is duplicated, most growth occurs

S phase

synthesis, dna is duplicated by cell, most other processes haulted

g2 phase

growth 2, some growth and cell processes occur, cell double checks duplicated dna for any errors

aypoptosis

cell kills any problematic dna (mutations)

mitosis

the process resulting in 2 identical nuclei, asexual reproduction

early prophase

nuclear membrane and nucleus disasemble, chromatin condenses into chromosomes. centrioles move to opposite poles and send out spindle fibers

prometaphase

late prophase. centrioles and spindle fibers form mitotic spindle. spindle fibers from both centrosome complexes attatch to sister chromatids via kinetochore

kinetochore

structures of protiens associated with sections of dna at the centromere

centrosome

complex centriole and spindle fibres

metaphase

sister chromatids get moved by spindle fibres to be lined up at the cell’s equator

anaphase

sister chromatids seperate and move to opposite ends of the cell as the spindle fibres contract

telophase

centrosome and spindle fibres dissasemble, nuclear membrane and nucleus form around both piles of chromosomes, chromosomes uncondense into chromatin

cytokenesis

cell membrane pinches into 2 identical cells. cytoplasm splits dividing the cell

cytokenesis in plant cells

cell plate forms between nuclei, no centriole but has similar structure

cytokenesis in animal cells

cleavage furrow develops between 2 cells, pinching them apart

3 reasons why cells undergo the cell cycle

growth, repair, replacement of cells

cancer

when cells begin to divide uncontrolobly