Science Chapter 4

large and contains food; formed in the ovaries of females

small with whip-like tails; formed in the testes of males

chromosomes are paired

have 1 chromosome from each pair

the joining of an egg and a sperm

the cell that forms after fertilization. It has a diploid # of chromosomes(23 chromosomes from each parent)

sperm-23 chromosomes+egg-23 chromosomes=zygote-46 chromosomes

a chemical that controls the acrivities of cells with coded information. it is found on the chromosomes in the nucleus of a cell.

in 1953 she used X-rays to show that DNA was a spiral form made of molecules

in the late 1950's made a model of the DNA molecule based on Franklin's work

Staircase unwinds

nitrogen base pairs seperate.An enzyme breaks the weak bonds that connect the bases together

new base pairs floating in the cytoplasm come and pair up with the pair attatched to the handrail.

sugar and phosphates form on the side of each new DNA strand

the process by which DNA copies itself

a section of DNA on a chromosome that directs the making of a specific protein made of amino acids

carries the code for making proteins from the nucleus to the ribosomes

the process that occurs during cell division, providing a relliable mechanism for transferring the genetic code from one gen. to the next

carries the code from the nucleus to the ribosomes

carries amino acids from the cytoplasm to the ribosomes

a permanent change in a gene or chromosome

a group of 3 nitrogen bases (triplet)