BIOLOGY MIDTERM 2
DNA
DeoxyriboNucleic Acid
CHROMOSOME (made of a single long molecule of DNA)
a thread like structure of dna, carrys genes
when not close to cell division
can not be seen (uncoiled and uncondensed) is called chromatin
when close to cell division
DNA replicated
each dupe cromosome has two sister chromatids (they separate during cell division)
centomere, narrow waist of duped cromosomes, where chromatids are most closely attached
formation
1)DNA in thin and uncoiled strands
2)DNA replicates
3)DNA coils
4)chromosomes --> DNA in 2 joined identical strands
the genetic information in
all living organisms which is transmitted from parents to offspring
usually in piles, like worms
in the nucleus of eukaryotic cells
when in cell division
gets duped into two chromatids that make it look like it's being ripped appart, held together by centromere
free in the
cytoplasm of prokaryotic cells
chromatids become chromosomes in telophase when the two nuclei form
structure
3d shape = double helix
telomeres,l at both ends
each chromatid contains one DNA molecule
DNA is a code for proteins
proteins have a structural and functional role
centromere has no genes
each chromosome is made up of thousands of genes
enzymes are proteins that control all chemical reactions in the cell
it contains a CODE for the sequence of amino acids in a protein
Karyogram, drawing of karyotype
GENE
22 homoglous pairs of non-sex chromosomes(autosomes)
sex chromosomes(X-F, Y-M) are placed seperately
whole set of genes = GENOME
chromosomes are numbered based on leangth, 1=tallest
karyotype= photo of all chromosomes in an organism
homoglous, one comes from mother and the other from father
chromatids are identical
each chromosome in homoglous pair contains genes for the same charactaristics in same location, called locus
in diploid cell each chromosome is present in a set maid of two paired chromosomes one from mother and one father
number of chromosomes does not corrispond to complexity of being
haploid cells
one set of chromosomes (in humans n=23)
in humans, gametes(sperm and ova) haploid
diploid
two set of chromosomes (in humans 2n=46)
all body cells not gamets are diploid