PdBio midterm 2 Flashcards
molecule
2+ atoms held together b y various forces or bonds
Types of bonding
covalent, ionic, hydrogen
covalent bonds
sharing of electrons between 2 nonmetal atoms
ionic bonds
transferring electrons between metal and nonmetal atoms (ex: NaCl)
hydrogen bonds
H partial positive charge bonding with an electronegative atom such as N, O, or F
4 types of macromolecules
carbohydrates, lipids, proteins, nucleic acids
monomers
many small molecules linked together to form polymers
monomer: simple subunit (mono=1)
polymer: longer chain (poly=many)
polymer formation done by…
dehydration
dehydration
removes a water molecule (needs energy/enzymes to help)
polymer breakdown done by…
hydrolysis
hydrolysis
water added back in each time a monomer is released (enzyme used to catalyze the breakdown)
Carbohydrates
- monomer?
- function?
- composition?
- bonds used:
- monomer = monosaccharide sugar subunit
- function: store energy & aid in cell recognition
- composition: C,H,O atoms
- bonds used: covalent
Lipids -monomer? -function? -composition? bonds used:
- monomer = glycerol & fatty acids
- function: store energy & add structure/protection
- composition: C & H atoms, clumped together
- bonds used: covalent no H bonds
Which macromolecule is non polar and insoluble in H2O?
Lipids
Proteins -monomer? -function? composition? bonds used:
- monomer = amino acids
- function: provide structure & communicate
- composition: C,H,O,N,S atoms
- 20 different amino acids with a different R group
- changing R group also changes pH and charge
-bonds used: depends on the structure
What does the R group of an amino acid determine
chemical characteristics > pH and charge
Nucleic Acids
- monomer?
- function?
- composition?
- bonds used?
- monomer = nucleotide
- function: storage, expression, transmission of genetic info
- composition: phosphate group, 5C sugar, and a base (C,U,T,A,G)
- bonds used: covalent & hydrogen
purines in DNA
Adenine (A) and Guanine (G)
pyrimidines in DNA
Cytosine (C) and Thymine (T)
Base pairs in DNA - which bases pair with each other?
A&T pair together
C&G pair together
Things to remember about DNA structure (3)
base pairing (ATCG) double helix - anti-parallel no hydroxyl group on 2'
purines in RNA
Adenine (A) and Guanine (G)
pyrimidines in RNA
Cytosine (C) and Uracil (U)
Base pairs in RNA - which bases pair with each other?
A & U pair together
C & G pair together
Things to remember about RNA structure (3)
base pairing (AUCG)
single strand
hydroxyl group on 2’
DNA stands for
Deoxyribonucleic Acid
RNA stands for
Ribonucleic Acid
General process of the Central Dogma
DNA transcribed to RNA translated to Proteins
Why is DNA replication necessary?
It is necessary because cells divide and they need double the amount of DNA so the resulting daughter cells will contain the correct amount of DNA
Types of DNA replication (3)
- conservative
- semi-conservative
- dispersive replication
What is the most common/popular type of replication? Explain it.
Semi-conservative = DNA replication produces DNA molecules with 1 parental strand and 1 newly made daughter strand
Where does replication begin?
Origin of replication - provides an opening called a replication bubble that forms two replication forks
How many origins of replication are found in eukaryotes and prokaryotes?
- eukaryotes may have multiple origins of replication
- prokaryotes (bacteria) only have 1 origin of replication
Where does DNA replication happen in a cell and in which way does it proceed?
DNA replication happens in the nucleus. It proceeds outward from the forks.
What is the direction of DNA replication?
5’ to 3’ direction in the primary structure of nucleic acids
What is the composition of nucleic acids (in more detail)?
- the 5’ end has the free phosphate attached to the 5’ carbon
- the 3’ end has an OH group attached to the 3’ carbon
- 2’ end has either (H) for DNA or (OH) for RNA
- Nitrogen base attached to 1’C on sugar (ATCG)
- nucleic acids are sequenced from 5’ to 3’
Directions of the leading and lagging strands?
- leading strand is moving TOWARD the replication fork in 5’ to 3’ direction
- lagging strand is moving AWAY from the replication fork in 5’ to 3’ direction
Players in DNA replication (7)
- helicase
- single strand binding proteins (SSBP)
- topoisomerase
- primase
- DNA polymerase III
- DNA polymerase I
- Ligase
Function of helicase
“unzips” DNA strands
Function f single strand binding protein (SSBP)
keeps the strands separated
Function of topoisomerase
loosens the tension to prevent supercoiling in the rest of the DNA strand
Function of primase
makes RNA primer so that the enzymes know where to start building
Function of DNA polymerase III
builds the new base (5’ to 3’)
Function of DNA polymerase I
removes RNA primers (Okazaki fragments)
Function of ligase
links the bases together