IMMS Flashcards
Where is the site of glycolysis
Cytosol of mitochondria
Where is the site of the krebs cycle
the matrix of the mitochondria
where is the site of the electron transport chain
cristae of mitochondria
site of chemiosmosis?
cristae of mitochondria
what is the relevance of the inner membrane of mitochondria in ATP synthesis
The inner membrane has ATP synthase embedded in it. H+ from ETC moving out of it produces ATP
What is chemiosmosis
the movement of ions across a semipermeable membrane, down their electrochemical gradient (example: movement of H+ through ATP synthase)
what occurs in the cytosol of the mitochondria
glycolysis
what occurs in the matrix of mitochondria
kreb’s cycle
what occurs in cristae of mitochondria
electron transport chain and chemiosmosis
Function of mitochondria
Site of respiration and energy generation in form of ATP
Function of ribosomes
site of protein synthesis
Rough ER function
Synthesis and processing of proteins (it is a network of branching sacs with ribosomes attached)
Smooth ER function
lipid synthesis (contains enzymes)
Function of golgi apparatus
processing and packaging of proteins (especially those that need to be exported from the cell) and lipids
function of cytoskeleton
to provide structural support and the movement of materials
Types and sizes of cytoskeleton protein elements
Smallest: microfilaments (actin) - ~ 5 or 6nmMid: Intermediate filaments (e.g. desmin, nuclear laminin, vimentin, keratin) - ~10nmBiggest: Microtubules - ~25nm
Peroxisomes function
Fatty acid and ethanol oxidation, contains catalase (converts 2 hydrogen peroxides to 2 waters + 1 oxygen - like in potato experiment)
Lysosomes
Contains acid hydrolases for digestion and recycling
What is lipofuscin
yellow-brown ‘wear and tear’ pigment granules made from lipid-containing residues of lysosomal digestion or from the peroxidation of lipids.
how can lipids be stored
in adipocytes as triglyceridesin cell membranes in lipoproteins (High density and low density)
where is glycogen stored
In adult of around 70kg:~100 - 120g in liver~400g in skeletal muscle
Functions of cell membrane
- it is a partially permeable membrane - regulates what goes in and out of cell- site of membrane receptors- acts as barrier: separates intracellular from extracellular
what other molecules does the phospholipid bilayer/cell membrane contain? What is the function of each of these substances?
Cholesterol – binds together phospholipids to support fluidity (bilayer has fluid mosaic model)Proteins – integral proteins act as transporters and peripheral proteins are involved in cell signallingGlycolipids & Glycoproteins – involved in cell signaling
Which cells synthesise elastin
fibroblasts
Function of fibroblasts?
Produce Extracellular matrix:- structural proteins (fibrous collagen and elastin)- adhesive proteins (e.g. laminin and fibronectin)- ground substance (glycosaminoglycans and glycoproteins) - (the jelly filling)
Which proteins are involved in generating ciliary movement
tubulin and dynein
define oncotic pressure
pressure caused by difference in protein concentration between solutions, in this case plasma and interstitial fluid, which causes water to move into the solution containing more proteins, in this case from the interstitial fluid into plasma. - type of osmotic pressure exerted by proteins, particularly albumin
osmotic pressure definition
pressure applied to
what is the function of tight junctions
they bind neigbouring cells together in an epithelial sheet to prevent the leakage of molecules between them
what is an adherens junction?
They join the actin bundle of one cell to a similar bundle in a neighbouring cell
what is a desmosome
desmosomes join the intermediate filaments of one cell to its neigbouring cell
what is a hemidesmosome
acnchors intermediate filaments from a cell to the basal lamina
function of gap junctions
allows the movement of small water-soluble ions and molecules (important for conduction of electrical impulses in the heart)
types of cell communication
Autocrine - Chemical released from cell into ECF and acts upon itselfParacrine - Local cellular communication; travels short distances i.e. ACh at NMJ. Paracrine chemical messengers travel in ECF.Endocrine - Secretion into blood NOT via duct. Long distance communication i.e. HPA axisExocrine - Secretion via ducts into organ (i.e. salivary and sweat glands)
modes of secretion
Merocrine – no part of the cell is lost with the secretion i.e. salivary glandsApocrine – top of the cell is lost with the secretion i.e. mammary glandHolocrine – the whole cell is lost with the secretion i.e. sebaceous glands
what percentage of total body weight is water?
around 60%
What do high density lipoproteins (HDLs) do?
transports cholesterol to liver to be metabolised and excreted via bile (this is good).They are produced in the liver
what do low density lipoproteins (LDLs) do?
transports cholesterol to cells (bad)| Produced in the plasma
Very low density lipoproteins (VLDL)
Synthesised in hepatocytes.| Transports triglycerides from liver to adipocytes
what does single strand binfing protein do?
keeps the two DNA strands apart during the synthesis of new DNA – prevents annealing (something about the hydrogen bonds breaking and reforming due to increases and decreases in temperature)
Describe transcription
- Topoisomerase unwinds the DNA double helix (relieves supercoils).- SSBs coat the DNA strands to prevent annealing- Free mRNA nucleotides line up next to their complementary bases on the template (antisense) strand (U-T, T-A, C-G, G-C). Begins at promotor region.- This forms antiparallel mRNA strand 5’ to 3’ - mRNA leaves the nucleus and attaches to 80S ribosome
describe translation
- mRNA attached to 80S ribosome- tRNA molecules have anticodons complementary to the codons on the mRNA strand on one end, and the amino acid corresponding to the codon on the other- Once two tRNA molecules are adjacent, a peptide bond is formed between the two amino acids.- This process repeats until stop codon reached- No tRNA binds to the stop codon, so the polypeptide is released into the cytoplasm
types of chromosomall abnormalities
Non-disjunction, numerical and structural
what is a numerical abnormality
when the individual has a different number of chromosomes e.g. 47XXY (Klinefelter syndrome)
what is a structural abnormality
When parts of an individual chromosome is missing, duplicated, transferred to another chromosome, or turned upside down. (Insertion, translocation).
what is gonadal mosaiscm?
A type of genetic moscaism where there is more than one set of genetic information present in the gametes and germ cell populations. It does not affect the parental somatic cells and may or may not affect the offspring. e.g. osteogenesis imperfecta.
what is lyonization?
X-inactivation: process by which one of the X chromosomes is inactivated in females
examples of purely genetic conditions
Down’s syndrome, haemophilia (bleeding disorder - can’t clot properly), Cystic fibrosis, Huntington’s disease, Edward’s syndrome (trisomy 18), Patau syndrome (trisomy 13)
examples of multifactorial conditions
spina bifida, cleft lip/palate, diabetes, schizophrenia
examples of purely environmental coditions
poor diet (kwashiorkor - thing that causes oedema in abdomen), infection, drug related illness, trauma related illness
what is the name for fluid collecting in your abdomen
ascites
what type of diseases are more common in more developed and less developed countries?
Multifactorial in more developed| Environmental in less developed
when does ketogenosis occur?
Occurs at a low rate during normal physiological conditions but rate increases when there is a shotage of carbohydrates for energy production (made from Acetyl CoA). The heart and skeletal muscles peferrentially uses ketone bodies so the brain can use glucose for energy (tho the brain can use ketones too if required).Also occurs during increased fatty acid beta oxidation which produces a lot of Acetyl CoA a lot of which can then be used in ketogenesis.Fat oxidation is also dependent on glucagon (activation) and insulin (inhibition) levels.
regulation of ketogenesis
- Release of free fatty acids from adipose tissue - increases ketogenesis- A high concentration of glycerol-3-phosphate in the liver results in triglyceride production, whilst a low level results in increased ketone body production.- When demand for ATP is high, acetyl-CoA is likely to be further oxidised via the TCA cycle to carbon dioxide.- Fat oxidation is dependent upon the amount of glucagon (activation) or insulin (inhibition) present
ketoacidocis: symptoms and who are most likely to be affected
Symyptoms: hyperventilating and vomiting| Common in: Type 1 diabetics (often the presenting feature in newly diagnosed) and in cases of cronic alcohol abuse
