Cell Biology Module 6: DNA Replication

What is the general function of DNA? (there are 2)

stores genetic instructions to make proteins

makes new cells by copying itself

what are the 3 parts of a nucleotide?

phosphate group

deoxyribose sugar

nitrogenous base (ATCG)

what forms phosphodiester bonds?

sugar + phosphate

what forms hydrogen bonds?

nitrogenous bases between strands

how many bonds does A-T have? (think AT&T)

2

how many bonds does G-C have? (a group chat has to have a minimum of how many people?

3

strands of complementary DNA run ______

antiparallel

what is at the 5’ end?

phosphate group

what is at the 3’ end?

OH group

why is the 3’ end important in replication?

DNA can only add nucleotides to the 3’ end

complementary nucleotides in the two DNA strands connect to each other using what kind of bond?

hydrogen

how do you build the bond between the nucleotides?

remove a H from the 3’ position of the last attached nucleotide and remove a OH from the phosphate group at the 5’ position of the new nucleotide

what does semiconservative mean?

one original strand and one new strand

Newly-synthesized DNA double helices are made of what two strands?

parent and daughter

what is an origin of replication?

starting point where DNA begins to open

what is a replication bubble?

opened region of DNA where copying occurs

what is a replication fork?

Y-shaped ends where DNA is actively being unwound and copied

what does helicase do?

breaks hydrogen bonds between the complementary strands and unzips DNA

what does topoisomerase do?

relieves tension ahead of helicase

what does primase do?

makes RNA primer

where is the primer attached?

to template strand

what does DNA PIII do?

attaches to primer, reads template, and builds complement

what does DNA PI do?

removes RNA primer and replaces with DNA nucleotides

what does ligase do?

joins okazaki fragments

how does ligase join okazaki fragments?

builds new phosphodiester bonds between them

why is the leading strand continuous?

built TOWARD replication fork

ligase joins the ____ end of DNA that replaces the primer to rest of leading strand DNA

3’

why is the lagging strand discontinuous?

built AWAY from replication fork

how does DNA PIII ensure accuracy?

proofread and fix incorrect bases immediately

what does nucleotide excision enzymes do?

remove large chunks of DNA that were incorrectly copied

a ____ is the complete set of DNA found in each of your cells

genome

DNA is coiled around ____ ____ and packaged into chromoses

histone proteins

________ contain genes that regulate general functions such as metabolism & growth (#1-22)

autosomes

____ ________ contain genes involved in sex determination & sexual reproduction as well as color vision and blood clotting

sex chromosomes

DNA is ____ stranded

double

What is the process used by a cell to copy its DNA?

replication

replication prepares the cell for what process ?

mitosis

how many ORI does bacterial chromosomes have?

1

how many ORI does human chromosomes have?

several

the _____ strand is oriented with the 3’ toward the replication fork and the 5’ toward ORI

leading

the ____ strand is oriented with the 3’ toward the ORI and the 5’ toward the replication fork

lagging

the first nucleotide is attached to the ___ ____

RNA primer