review Flashcards
Platelets
Platelets are involved with clotting blood when blood vessels break. When a blood vessel is damaged, platelets send out signals that trigger an immediate travel to the injured area in order to form clots and stop the bleeding.
What are the benefits of blood clotting when skin is cut?
One of the benefits of blood clotting is that it protects the wound’s surrounding tissues. Another benefit of blood clotting is that it provides a provisional matrix allowing cells to migrate to the injured area during the repair process.
Macrophages
Macrophages are phagocytic white blood cells. The role of macrophages is to engulf and digest pathogens in order to maintain homeostasis. This is done by first detecting the pathogens through the chemicals it releases. Then, it ingests the pathogen by wrapping itself around it. Then, it fuses with a lysosome to digest and break down the pathogen. Then, the broken down material is discharged.
B lymphocytes/B cells
A B lymphocyte (B cells) contain antibodies attached to its surface and have unique binding sites. When the B cell encounters an antigen, the B cells divide through mitosis to create multiple copies of itself. These copies become plasma B cells which produce antibodies and memory B cells so your immune system can recognize the antigens in the future.
Antigen versus antibody
An antigen is a specific molecule found on pathogens that triggers an immune response. Antibodies are proteins that are released from plasma B cells. Antibodies’ shape allows them to bind to and inactivate specific antigens.
Helper T-cell
Helper T-cells help B cells make antibodies. The APC (Antigen Presenting Cell) traps the antigen and presents it to the T helper cell. Once the antigen has been recognized by the T helper cell, it triggers the production of antibodies and activates macrophages to engulf and destroy the pathogen.
Agglutination
Agglutination is the clumping of a liquid. It occurs when an antibody binds to an antigen. If an individual with blood group A receives blood type B during a transfusion, anti-B antibodies will be produced and agglutination will result.
Histamine and antihistamine
Histamine is produced by white blood cells (basophils and mast cells). Its function is to dilate and increase permeability of capillaries. This enables white blood cells to invade infected tissues and engage allergens. Some allergic symptoms caused by histamines include itchiness, swelling, and sneezing. Antihistamines are drugs that inhibit the action of histamines by blocking histamine’s receptors.
DNA replication
Helicase unwinds DNA into single strands allowing each strand to be copied. Gyrase unwinds the supercoil to prevent DNA from breaking. Single stranded binding proteins keep the DNA strands separated and stabilized. Primase adds RNA nucleotides to the complementary base pairs. DNA Polymerase III adds RNA primer sequence in a 5’ to 3’ sequence. DNA Polymerase I digests RNA primers and replaces them with DNA nucleotides. Ligase joins the okazaki fragments on the lagging strand to form a single strand of DNA.
Mitosis
Mitosis produces two genetically identical daughter cells from a single parent cell. In prophase, chromosomes condense forming two chromatids. The nuclear membrane disintegrates causing the spindle to form. In metaphase, the spindle organizes chromosomes on the equator of the cell. Some spindle fibers attach to the centromeres and some span the cell. M-checkpoint occurs. In anaphase, some spindle fibers shorten which pull the chromatids apart. Some spindle fibers lengthen which cause the cell to elongate. In telophase, two new nuclei form.
Meiosis I
Meiosis produces 4 cells containing half of the original amount of DNA from the original parent cell which divides twice. In prophase I, the nuclear membrane dissolves. The spindle fibers start to form crossing over. In metaphase I, paired chromosomes line up at the equator of the cell. A spindle fiber attaches to each pair. In anaphase I, the spindle fibers pull the paired chromosomes apart. In telophase, the chromosomes arrive at opposite poles of the cell and the nuclear membrane reforms.
Meiosis II
Meiosis produces 4 cells containing half of the original amount of DNA from the original parent cell which divides twice. In prophase II, the nuclear envelope breaks. The spindle fibers form between centrosomes. In metaphase II, the unpaired chromosomes line up at the equator of the cell. In anaphase II, the unpaired chromosomes separate and are pulled to opposite poles of the cell. In telophase II, the nuclear membranes begin to reform around new chromosomes. Then, the chromosomes decondense.
