the patient Flashcards
what are the purine bases
adenine
guanine
what are pyramidine bases
cytosine
thymine
helicase
unwinds the DNA double helix by breaking hydrogen bonds
what are single stranded binding proteins (SSBs)
stabilises single strands
what’s primase
makes short pieces of RNA to ‘prime’ DNA synthesis
what is DNA polymerase
polymerises DNA, according to the template from dNTPs
what’s ligase
seals breaks (okozakki fragments) during synthesis of DNA
what do topoisomerase do
mentain supercoiling
what are the three stages of transcription
initiation
elongation
termination
what’s initiation
requires a promoter
what’s elongation
nucleotides/NTPs are added to the growing RNA chain by RNA polymerase with the loss of PPi each time.
what’s termination
stem loop becomes elongated in the polymerase. and the complex dissociates with or without a factor called RNA polymerase
describe the in detail process of termination
D) TFIID: recognised and binds to TATAbox via TBP
A) TFIIA: binds non specifically to DNA and stabilises the DNA/TFIID interaction
B) TFIIB: binds to the promoter assembly
F) a complex of RNA polymerase II and TFIIF binds to the assembly
E/H) finally, TFIIE and TFIIH bind allowing transcription to commence
what is capping
(eukaryotic pre-mRNA processing)
guanine is attached in an S-S bond, cap G is methylated in the 7th position
what is polyadenylation
(eukaryotic pre-mRNA processing)
adds up to 250 A’s
what is intron splicing
(eukaryotic pre-mRNA processing)
joins exons (coding regions) to form a whole gene. eukaryotic pre-mRNA has GT-AC class introns
why are 20 amino acids sufficient
because they produce 64 codons
Describe the process of translation in detail
1) the small ribosomal subunits attaches to the ribosome binding site in a sequence of 5’ to 3’
2) the small ribosomal subunits moves down stream to the start codon AUG
3) the first transfer RNA Binds
4) the large subunit binds. [requires hydrolysis of.GTP]
5) the second tRNA binds to A site. requires EETu
6) a peptide bond is formed by peptidyl transferase
7) tRNA is freed from the amino acid by tRNA deacylase
8) translocation occurs requires the hydrolysis of GTP again
9) stage 5 to 8, are repeated until
10) a stop codon is encountered [no more tRNA exists]
11) RF1/RF2 Binds, and clears the polypeptide from tRNA in the P site. RF3 co operates
how do you measure the haematocrit
Take a blood sample in a tube. The red blood cells sink and the white blood cells are in the middle and the plasma sits on top.
Spin in a centrifuge and the normal red blood cell count is between 40 and 50%
What is anemia?
A condition where the blood cannot to transport enough oxygen to the tissues
What is malaria?
where some red blood cells have a malaria parasites in them. And eventually the red blood cell is destroyed. There is a low red blood cell count.
what’s haemostasis
A process of keeping the blood from being lost from the vascular system. [Stopping bleeding] from clot formation, and tissue repair.
what is hemophilia
Insufficient blood clotting
what is thrombosis
Weather is too much blood clothing. This prevents blood loss, but can lead to cardiovascular disorder.
Capillary exchange: how does oxygen get into tissues and cells and the reverse for carbon dioxide?
hemoglobin carries oxygen to the capillaries
At the arterial end, that is a high blood pressure water is pushed out of the blood vessel, and all the fluid is pushed out
Proteins remain in the capillary and produce colloid osmotic pressure. dispose of water in and the colloid pressure is constant.
The bulk of the flow of oxygen and water and glucose out at the arterial end. That is bulk flow of carbon dioxide and waste in on the venue will end.
There is net outflow into the extracellular fluid and about 2 L a day of blood is collected by the lymph assholes
What consists of the lymphatic system/vessels?
capillaries and valves (to ensure one-way flow)
Lymph vessels
Lymph nodes and valves
What is the role of the lymphatic system?
It returns to plasma
It is involved in immunity and the creation of antibodies
What are five functions of the blood?
1) transportation of dissolved gases, nutrients, hormones, and metabolic waste
2) regulation of the pH and electrolytes composition of intestinal fluids throughout the body
3) restriction of fluid losses
4) it is a defense against toxins and pathogens
5) stabilization of body temperature
What two things is blood composed of
plasma: water, ions, organic molecules, trace elements and vitamins, gases
Cellular elements: red blood cells, white blood cells, platelets
What is the structure of hemoglobin?
It’s consists of full polypeptide chains 2Alpha and 2Beta
The iron ion in the haem is able to reversibly bind to an oxygen molecule
What is a white blood cell: neutrophil
they are phagocytotic: they engulf bacteria
A high neutrophil count indicates a bacterial infection
What are white blood cells: lymphocytes
B cells/T cells: they secrete antibodies
A high count suggests an infection
what is haematopoiesis
blood cell formation
Pluripotent haematopoietic stem cells, uncommitted stem cells, comfifed progenitor cells, lymphocytes stem cells, lymphocytes
what is bone marrow?
Bone marrow consists of blood cells, in different stages of development and supporting bone tissue, known as the stroma
what is erythropoiesis
where blood cell maturation is regulated.
what is rRNA
Ribosomal RNA: the ribosome itself is made of this
What are cell surface receptors?
Cell surface, receptor proteins are hydrophilic signal molecules that sit in the receptor
What are intracellular receptors?
small hydrophobic, signal molecules carried into the target cell via a carrier protein. Intracellular receptors are located in the nucleus.
What is a ligand?
it is a molecule that binds to a receptor
Some receptors only have one ligand whilst other receptors have many
What is a fun fact about ligands
different ligands can produce different responses at the same receptor
agonist/antagonist
What is an intracellular mediator?
Proteins that transmit the signal from the receptor to the effect enzymes
What are effector enzymes?
they bring about changes in the cell by the production of second messengers
What are second messages
they alter the metabolism or affect effector enzymes that modulate target proteins
What are target proteins?
they alter gene transcription and cell behavior
receptor tyrosine kinases
Transmembrane proteins
what’s a dimer
They consist of two of the same proteins that come together
What do kinases do?
they had a phosphate to proteins using ATP
How is tyrosine phosphorylated by kinase in detail
The ligand binding site formed on both molecules of the dimer
Two molecules come together to trap the ligand
This results in two intracellular domains coming together
Then tyrosine is phosphorylated by kinase
What is RTK signaling
it can use monomeric G proteins as molecular switches
GDP to GTP
GTP binding activates signaling
what does phosphorylation and GTP binding do
Both act as molecular switches, both can amplify signalling strength, both need turning off
what is the MAP kinase cascade (detail)
ligand/signal molecule binds
activated RTK
adaptor protein to ras-activating protein
inactive ras protein to active ras protein via GTP
onward transmission of signal
activated MAP kinase x3 (ATP to ADP)
activated MAP kinase x2 (ATP to ADP)
activated MAP kinase
what are the three steps in inactivation of receptor signaling?
1) signal molecule binds to a receptor protein
2) inactivation of signaling protein
3) production of inhibitory protein
(the complex forms an endsome with lysosomes)
What two types of switch does the MAP kinase pathway use
1) phosphorylation
2) small monomeric, G proteins
what is a GPCR
G protein coupled receptor
They are the largest class of human cell surface receptors
describe the process of GPCR activation
1) Ligand binds to the extracellular site
2) confirmational change occurs to the receptor
3) this recruits, inactive G protein (GDP bound)
4) binding to the receptor releases GDP, which is replaced by GTP
5) Galpha separates to activate signaling Cascades
6) an activated GPCR activates many G proteins
what else can G proteins activate
cAMP
converts ATP to cAMP
where cAMP is a second messenger
what are the cellular effects of Ca2+
they activate calmodulin
Activated calmodulin activate calmodulin dependent kinases. Which modulate activity of other proteins.
How can G proteins control channel opening [2 ways.]
indirectly: second messages, phosphorylation
Directly: binding of to ion channels
What are receptor signaling Cascades?
they can detect a single molecule of ligand
Transduce this signal across the membrane
Rapidly amplify the signal
Activate a cascade of proteins that bring about cell behaviors
