genetics in the cell cell membrane nucleus cytoplasm
TRANSCRIPT
Genetics in the Cellcell membrane
nucleuscytoplasm
In the nucleus of a cell:
chromosomes – made of many different genes
genes – hold the genetic information for each trait
All the body cells of humans have
46 chromosomes
meiosis is the process used to make gametes (sex cells)
gametes have ½ the # of chromosomes in the body cells
Human gametes have 23 chromosomes
organism chromosomes in body cells
chromosomes in gametes
human
chickengoldfish
antcorn
Horsetail fernbutterfly
chimpanzee
4678104
220
210380
48
2339521
1010519024
chromosomes are made of supercoiled DNA
DNA (DeoxyriboNucleic Acid)structure discovered in 1953 by James
Watson and Francis Crick
Watson, Crick and Maurice Wilkins won the Nobel Prize in 1962
DNA is shaped like a double helix (a twisted ladder)
sides – alternating molecules of sugarand phosphate
(deoxyribose)
rungs – four types of nitrogen bases: Adenine (A)Thymine (T)Guanine (G)Cytosine (C)
always bond
always bond
ATAGCTTGACG
TATCGAACTGC
nitrogen bases attach to sugars (deoxyriboses) not phosphates
nitrogen bases are attached with hydrogen bonds
A -- T
DNA is made of units called nucleotides.
Each nucleotide has a sugar, a phosphate and a nitrogen base.
(deoxyribose)
and so on…