Huabing (Block 1 ENG in Bio) Flashcards
What is a hydrogen bond ?
A polar interaction in which an electropositive hydrogen atom is
partially shared by two electronegative atoms
What is a ionic bond ?
Attractive forces between oppositely charged atoms
What is a covalent bond ?
Formed by the sharing of electrons
What is Van der Waals attraction ?
the interaction between opposite dipoles of atoms
What is the use of Hydrophobic force for bonding ?
Is not a bond, but caused by a pushing of nonpolar surfaces out of the
hydrogen-bonded water network
Typical covalent bonds are stronger than thermal energy by a factor of ?
100 therefore not easily pulled apart by heating
What type of bonds specify the precise shape of a macromolecule ?
Non-covalent
What is a macromolecule ?
A macromolecule is a very large molecule, such as a protein. They are composed of thousands of covalently bonded atoms. … The most common macromolecules in biochemistry are biopolymers (nucleic acids, proteins, and carbohydrates) and large non-polymeric molecules such as lipids and macrocycles
What form of movement do covalent bonds allow in a macromolecules and how is this countered ?
Rotational, countered by many non-covalent bonds to hold in place
What bonds link amino acids together and what is what is forms called ?
Covalent peptide bonds, together form the polypeptide backbone.
What determines the precise shape of a protein ?
It’s amino acid sequence
What does the side chain do in a protein ?
The side chain gives each amino acid
unique properties and are involved in forming noncovalent bonds to help proteins fold.
What 3 types of non-covalent bonds are used in protein folding ?
Van der waals , Hydrogen bonds and electrostatic bonds (ionic bonds ).
What force can be involved in protein folding ?
Hydrophobic forces (when in water ).
Proteins generally fold into a shape in which _____ is minimised ?
Free energy
What are the most structurally diverse macromolecules in the cells ?
Proteins
What are the 2 most regular folding patterns for proteins ?
Alpha helix and the beta sheet
What is the primary structure of a protein ?
It’s amino acid sequence
What is the secondary structure of a protein ?
Alpha helices and beta sheets that form within certain segments of the polypeptide chain.
What is the tertiary structure of a protein ?
The full 3D conformation, is formed
by an entire polypeptide chain, including the alpha helices, beta sheets, and any other folds
What is the quaternary structure of a protein ?
The complete structure of a protein ,if the protein is formed out of several polypeptide chains.
What is a Protein domain ?
A protein domain is defined as any segment of a
polypeptide chain that can fold independently into a compact, stable structure
What is a protein family ?
proteins consisting of similar amino acid sequences and 3D conformation are unusually
grouped as a protein family
Larger protein molecules often contain more than one polypeptide chain. Any region on a protein surface that has this capability is termed?
A binding site
Each peptide chain in a large protein with multiple chains is called ?
A subunit.
In addition to the non-covalent bonds, ___________ between polypeptide chains are often formed to reinforce the structure of proteins (name the most common )
covalent cross-linkages (Disulfide)
Any substance that is bound by a protein is referred to as a ______ for that protein
Ligand
Each antibody can recognize and bind to a particular target (called an _______) extremely tightly
antigen
What shape is an Antibody ?
Y shaped
Antibodies are formed from four __________ held together by ________ bonds: two are identical ______
chains and two identical _______ chains.
1 .Polypeptide chains
- disulfate
- heavy
- light
The antigen binding site of an antibody is formed by ?
Close association of variable domains from heavy and light chains.
Antigen binding site complementary to a site on the antigen (known as the ________) in terms of shape and the arrangement of ________ and _______ groups
- epitome
- hydrophobic
- charged
The movements of protein machines is coordinated by what ?
The hydrolysis of a bound nucleoside triphosphate (ATP or GTP).
What does the plasma membrane do ?
Acts as a selective barrier to maintain a constant intracellular composition
The ___________ senses the external signals and allows the cell to change its behavior in response to the signals
plasma membrane
What makes up the lipid bilayer ?
Lipids arranged in two closely apposed sheets. The hydrophilic heads are attracted to the water molecules and the hydrophobic repel.
What does the lipid bilayer do ?
Serves as a permeability barrier to most water-soluble molecules
Describe a lipid molecule
A hydrophilic head and 1 or 2 hydrophobic hydrocarbon tails known as amphipathic
The fluidity of the lipid bilayer depends on what ? And explain how this effects fluidity
On it’s composition, the more closely packed the hydrocarbon tails are the more viscus and less fluid the bilayer becomes
Read from lecture 4 slide 9 to end These are hard to question on without images.
I did it .
Name the 4 types of signaling between cells
Endocrine signaling ,paracrine signaling, neuronal signaling,contact-dependent signaling.
Describe endocrine signaling
Endocrine cells secrete hormones into the bloodstream, affecting the target cells anywhere in the body
Describe paracrine signaling
The signal molecules diffuse locally through the
extracellular fluid, acting as local mediators
Describe neuronal signaling
Neuron cells can deliver electrical signals over long distances
Describe contact-dependent signaling
The signal molecules on the surface of the signaling cell are in direct physical contact with the receptor
proteins on the surface of the target cells
Name and describe the 2 classes of receptor
1. The first and largest class rely on cell-surface receptors to relay their message across the plasma membrane.
- The second class are generally small and hydrophobic molecules that can diffuse through the membrane. Once inside they usually bind to intracellular receptors.
What regulates the activity of specific intracellular proteins ?
Nitric oxide
Many key intracellular signaling proteins behave as __________?
Molecular switches
Describe and draw protein phosphorylation and signalling by GTP
Found on block 1 L5 slide 7
What are the 3 families of cell-surface receptors ?
Ion-channel coupled receptors,G-protein-coupled receptors, enzyme-coupled receptors
What are ion-channel-coupled receptors responsible for and what do they do ?
They are responsible for the rapid transmission of signals across synapses in the nervous system and they convert chemical signals into electrical ones
Read Block 1 L5 silde 9-15
DONE ?
