biology - chromosomes

chromatin

NON-DIVIDING long strands of DNA that hold/carry genes

genes

provides information about who we are

ex. hair color, eye color

allele

half of a gene (meaning 1 half from mom or dad)

zygote

fertilized egg

centromere

the point where to chromosomes meet and connect

telomere

the cap found at the end of each chromosome arm

used to protect the chromosome when it duplicates but, it becomes shorter each duplication

DNA and mtDNA

DNA = composed of nucleotides and looks like a twisted ladder

mtDNA = DNA found in the mitochondria that comes from the maternal (mother) side

phosphate group

PO3H2

nitrogenous bases

Adenine (A)

Cytosine (C)

Guanine (G)

Thymine (T)

what does every chromosome have?

2 matching strands, a phosphate group, sugar on the outside, nitrogenous base in the center.

Watson, Crick, Wilkins, and Franklin

4 scientists produced a 1 page paper explaining DNA and proving that it has a helical shape

they won the nobel prize in 1962 (franklin didn’t get it because she died)

how did this experiement become possible?

Franklin (the best scientist in her field) received an x-ray of crystallography

chargaff’s rule

scientific bases are always paired with other specific bases

Adenine to Thymine

Cytosine to Guanine

somatic chromosomes

non gender cells

for example: bones and blood cells

gender chromosomes

female = XX, male = XY

histones

wrap around DNA to protect it

karyotypes

a chromosomal map that is used to study gender chromosomes

long arm

the longest part of the chromosome from the centromere “q”

short arm

shortest part of the chromosome from the centromere “p”