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33 Cards in this Set

  • Front
  • Back
Most Protein-ligand interactions do not involve __ _______ _____. Instead, the binding site for a ligand is more often like the hemoglobin binding site for BPG - .....
- a prosthetic group.

- A cleft in the protein lined with A.A residues, arranged to render the binding interaction highly specific
Effective discrimination between ligands ___ ____ ____ at binding sites, even when the ligands have only minor structural differences
- is the norm
All vertebrates have an immune system capable of distinguishing _____ _____ ______ _______ and then destroying those entities identified as ________
- molecular "self" from "nonself"

- nonself.
All vertebrates have an immune system capable of distinguishing self from non-self and then destroying those entities identified as nonself. In this way, the immune system eliminates
- viruses, bacteria, and other pathogens and molecules that may pose a threat to the organism
On a physiological level, the response of the immune system to an invader is an ?
- intricate and coordinated set of interactions among many classes of proteins, molecules, and cell types
Immunity is brought about by ?
a variety of leukocytes including macrophages and lymphocytes, all developing from undifferentiated stem cells in the bone marrow
Leukocytes can leave the bloodstream and patrol the tissues, each cell producing ?
- one or more proteins capable of recognizing and binding to molecules that might signal an infection
The immune response consists of two complementary systems,
- the humoral and cellular immune systems
The humoral immune system is directed
- at bacterial infections and extracellular viruses, but can also respond to individual proteins introduced into the organism
The cellular immune system destroys
host cells infected by viruses and also destroys some parasites and forgein tissues
The proteins at the heart of the humoral immune response are soluble proteins called
- antibodies or immunoglobulins often abbreviated Ig.
Immunoglobulins bind bacteria, viruses, or large molecules identified . . .
- as forgein and target them for destruction
Making-up 20% of blood protein, the immunoglobins are produced by ....., so named because they complete their development in the bone marrow
- B lymphocytes or B cells
The agents at the heart of the cellular immune response are a class of . . .
T lymphocytes aka T cells

AKA: cytotoxic T cells, T[c], or killer T cells
T lymphocytes are called that because
the latter stages of their development occur in the thymus
Recognition of infected cells or parasites involves proteins called _______ _______ on the surface of T[c] cells
T-cell receptors
Receptors are proteins, usually found on . . . . .
* the outer surface of cells and extending through the plasma membrane

* they recognize and bind extracellular ligands, triggering changes inside the cell
In addition to cytotoxic T cells, there are helper T cells (T[h] cells], whose function it is to
- produce soluble signaling proteins called cytokines, which include the interleukins
T[h] cells interact with _________.
Each recognition protein of the immune systems, either an antibody produced by a B cell or a receptor on the surface of a T cell, specifically binds some
- particular chemical structure, distinguishing it from virtually all others
Humans are capable of producing more than ______ different antibodies with distinct binding specificities
Humans are capable of 10^8 different antibodies with distinct binding specificities. This extraordinary diversity makes it likely that
- any chemical structure on the surface of a virus or invading cell will be recognized and bound by one or more antibodies
Antibody diversity is derived from
- random reassembly of a set of immunogloblin gene segments throughout genetic recombination mechanisms
Some properties of the interactions between antibodies or a T-cell receptor and the molecules they bind are unique to
- the immune system, and a specialized lexicon is used to describe them
Any molecule or pathogen capable of elicting an immune response is called . .
an antigen
Antigen may be . . .
- a virus, a bacterial cell wall, or an individual protein or other macromolecule.
A complex antigen may be bound by ...
a number of different antibodies
An individual antibody or T-cell receptor binds only a particular molecular structure within the antigen, called its . .
antigenic determinant or epitope
Molecules of M[r] < 5000 are generally not
Macrophage function
Ingest large particles and cells by phagocytosis
B lymphocytes (B cells) function
Produce and secrete antibodies
T lymphocytes (T cells)functions:
Cytotoxic (killers) and T Cells (T[c])
Interact with infected host cells though receptors on t-cell surface
T lymphocytes (T cells)functions:
Helper T cells (T[h])
Interact with macrophages and secrete cytokines (interleukins) that stimulate T[c], T[h], and B cells to proliferate