What are the 2 nitrogen bases for pyrimidines?
cytosine, thymine
What is the symbol for adenine?
A
What is the symbol for guanine?
G
What is the symbol for cytosine?
C
What is the symbol for thymine?
T
What is it called when DNA looks like a twisted ladder?
double helix
Of the DNA ladder, what are the rungs?
nitrogen bases
What are the "backbone" or "sides" of DNA?
alternating sugar and phosphate groups of each nucleotide
What does a purine match with at the opposite strand?
pyrimidine
Which nitrogen base pairs with adenine?
thymine
Which nitrogen base pairs with guanine?
cytosine
The pairing of these bases are known as...
Chargaff's Rule
The scientist who determined the base pairs are in equal concentrations or numbers
Chargaff
What does a cell do before it divides?
it replicates its DNA
When DNA replication is occuring, what happens to the 2 strands?
it seperates to produce complementary strands
What does the original DNA strand best represent as?
new strand template
What is the 1st part of DNA replication?
DNA helicase
it breaks the base pairs and opens up the molecule like scissors
DNA helicase
Who helps the DNA helicase cut the base pairs?
enzymes
What is the 2nd part of DNA replication?
DNA polymerase
it moves along each of the strands and adds complementary new base pairs to the original strand, creating 2 new double helixes
DNA polymerase
it proof reads each new DNA strand to ensure a perfect copy
DNA polymerase
More demands placed on cell and its DNA
cell growth
Less efficient diffusion
cell growth
Why is replication so important?
When cells get too large, dividing them avoids more demands placed on cell and less efficient diffusion
What happens before division occurs?
DNA is replicated
What 2 things make up chromosomes?
DNA, proteins
Does every organism have a specific number of chromosomes?
yes
When are chromosomes formed?
during division
What happens when chromosomes are not in division?
they are chromatids
What happens before chromosomes get divided?
they are copied so each daughter cell gets a complete set
What 2 identical things are chromosomes made of?
sister chromatids
What are chromosomes connected by in the middle?
centromere
Is Interphase in mitosis?
no
G1= growth
interphase
S= replication, DNA and proteins are synthesized
interphase
G2= the cell prepares for mitosis
interphase
Where does mitosis take place?
somatic cells
if somatic cells contain 2 copies of 23 chromosomes, how many chromosomes are there?
46
What is it called when somatic cells contain 2 sets of chromosomes?
diploid
If the new cell that is formed is identical to the original cell, mitosis is considered what?
asexual
Which phase takes up 50-60% of mitosis?
prophase
Which phase do chromosomes become visible?
prophase
Which phase does it occur in when centrioles begin to separate and move to opposite ends of the nucleus?
prophase
Which phase is when spindle fibers appear?
prophase
Which phase does the nucleolus disappear and the nuclear envelope breaks down?
prophase
Which phase only lasts a few minutes?
metaphase
Which phase do chromosomes line up at the center of the cell, along the equator?
metaphase
Which phase do the microtubules connect the centromere of each chromosome to the 2 poles of the spindle?
metaphase
Which phase does this occur when the centromeres split and the sister chromatids separate to finally become individual chromosomes?
anaphase
Which phase does it happen when the chromosomes move away to opposite ends of the cell, like polar migration?
anaphase
What happens when chromosomes are done moving?
anaphase is over
What phase does this belong in when chromosomes uncoil into chromatin?
telophase
If the nucleus re-forms around each cluster of chromosomes, the spindle disappears, and the nucleolus reappears, which phase is it?
telophase
Division of the cytoplasm
cytokinesis
Usually the cell membrane is drawn inward until the cytoplasm pinches into 2 cells, which are called daughter cells. Where does this belong in?
cytokinesis
When plant cells form a cell plate between the dividing nuclei, and the plate develops into a separating membrane, where does this belong in?
cytokinesis
What are those changes in the genetic material, that occurs during protein synthesis, and some are have benefits, and others have bad side effects?
mutations
What is it called when there is an uncontrolled growth of cells?
cancer
Do cancer cells respond to the body's signals that regulate cell growth and division?
no
Which tumor does not spread to nearby healthy tissue?
benign
Which tumor invades and destroys surrounding healthy tissue?
malignant
How is cancer caused?
defects in the genes that regulate cell growth and division
What are the 4 main ways that can damage the regulating genes?
tobbaco, radiation, other defective genes, viral infection
Many cancers have a defect in a gene which is called?
p53
Normally halts the cell cycle until all chromosomes have been replicated
p53
What is mainly called "the library"?
nucleus
What holds DNA?
nucleus
What is mainly called a "cookbook"?
chromosome
What is mainly called a "recipe"?
gene
What is mainly called the "paper" for the cookbook and recipe? *Hint= this is what the nucleus holds
DNA
What is the mainly called the "final product of what you make"?
protein
What does DNA stand for?
deoxyribonucleic acid
What are the 3 things that make up a nucleotide?
deoxyribose, phosphate group, nitrogen base
What is the "circle" in the nucleotide?
phosphate group
What are those lines that hold the shapes of the nucleotide in place?
covalent bonds
What is the "pentagon" in the nucleotide?
sugar (deoxyribose)
What is the end part of the nucleotide?
nitrogen base
When 2 nitrogen containing bases are partnering, what holds them together?
hydrogen bonds
DNA is made up of long molecules of units called what?
nucleotides
What are the 3 components nucleotide is made up of?
deoxyribose, phosphate group, nitrogen base
How many nitrogen bases are in DNA?
4
Double-ring molecules.
purines
What are the 2 nitrogen bases for purines?
adenine, guanine
Single-ring molecules
pyrimidines