Scriptures Flashcards
Isotonic point
Isotonic point- any external solution, has same solute conc and water conc, compared to body fluids (no net movement of water will take place).
Uncommon functions of triglycerides
electrical insulation and buoyancy and physical protection (for organs).
The hydrophilic heads of the phospholipid bilayers face towards…
an aqueous solution
where is the cambium / meristem located?
Cambium / meristem is whats in between the xylem and phloem (xylem bigger and towards the middle).
what do electron microscopes require the specimen to be in?
a vacuum, so they can’t be alive.
give 2 examples of autoimmune diseases
Autoimmune disease, arthritis (painful inflammation of membranes at joints), Lupus (antibodies to cell nuclei cause swelling and pain).
what does helpful microflora do?
Helpful microflora compete with pathogens on skin.
Mast cells, and damaged white blood cells in the damaged connective tissue and around blood vessels near the damaged tissue, release…
chemicals such as histamine, which increases blood flow to area. Histamine also increase capillary permeability, enabling the leak of plasma fluid, white blood cells and antibodies from blood into damaged tissue, causing swelling. Pathogens then targeted by white blood cells for destruction.
Phagocytes (Neutrophil or Macrophage) present
pathogen’s antigens to the specific immune system.
Antigen presenting cells recruit…
specific T and B cells in clonal selection and expansion for specific immune responses. Clonal selection involves selecting correct cell, and its subsequent division by mitosis is clonal expansion.
B cells, form plasma cells, with the function of…
releasing antibodies
B memory cells and T memory cells
for long term immunity (long-lived cells that remain dormant in lymphatic system / immune system).
T killer cells
attack and kill (by releasing chemicals), infected body cells displaying antigens.
T helper cells
release cytokines to stimulate B cells.
T regulatory cells
shuts down immune response when finished.
how are helper T cells activated?
A T helper cell with a complementary-shaped CD4 receptor on its surface can bind to this antigen on the antigen-presenting cell, leading to the activation of the T helper cells.
Monohybrid inheritance
inheritance of a single gene
Dihybrid inheritance
inheritance of 2 genes
what is codominance, give example
where both alleles expressed in the phenotype.
E,g Blood type.
whats the meaning of pure breeding parents?
both homozygous and opposites
GG (homozygous dominant), gg (homozygous recessive).
Haemophilia
e.g sex-linked genetic disorder, patients suffer having blood, clots extremely slowly (due absence protein-clotting factor).
If male inherit recessive allele on their X chrom, cannot have dominant allele on their Y chrom, so develop condition.
if the rate of apoptosis is too low, what could it lead to?
tumors could being to form
what are mutations caused by?
caused by mutagens (chemical / agents)
what are the different types of mutations, associated with the sequence of amino acids?
Insertion and Deletion (cause frameshift), Duplication and Inversion.
Point mutation involves a base substitution, can be silent (has no effect), missense (changes AA’s primary structure), or nonsense (introduces early stop codon, truncating the protein).
Phenotypic Variation
caused by enviro-factors (which can influence gene expression), not passed on through genes.
Homoebox genes
ancient, highly conserved genes, code for homeodomain sequences in protein that regulate anatomical development.
Role of Hox genes
regulate the axes of embryos, dictating the position of anatomical features. The spatial and temporal expression of Hox genes controls where and when parts of body develop.
what is tightly regulated for Euk and Pro cells?
transcription of genes
in Pro cells what regulates the transcription of metabolic genes?
the lac operon
explain how the lac operon works?
When lactose is present, inhibits the repressor protein, allowing RNA polymerase to transcribe lacZ and Y (the structural genes) for lactose metabolism.
in Euk, how does transcription factors control transcriptions?
by binding to promoter regions of genes and encouraging or inhibiting, binding of RNA polymerase.
Phenotypic variation, caused by genetic changes during when?
cell division
when do chromosomal mutations occur?
Chrom mutations, occur in meiosis (e.g Downs / Turner syndrome).
Types of chrom mutations
Duplication, Inversion, Deletion, Insertion and Translocation.
Meiosis produces … … …, due to …
Meiosis produces genetically distinct gametes, due to allele shuffling in crossing over and independent assortment.
Non-disjunction mutation involves…
changes to the chromosomal number during meiosis, as a result of homologous pairs of chroms not separating during first division (meaning some gametes have extra chroms and other have fewer than normal number).
how do enzymes actually denature when the temp is too high?
Denaturing of enzymes, when temp to high the hydrogen bonds what breaks, changing structure and shape.
how can high blood glucose levels be damaging and potential fatal to an organism
Blood Glucose conc in blood too high, causes water potential drop, water diffuses out from cells by osmosis into bloodstream, causing cells to be flaccid and die.
how are multiple negative feedback mechanisms more beneficial, then just one?
Negative feedback can only maintain internal environment within a specific range.
Multiple negative feedback mechanisms provide a greater degree of control of the internal environment.
Positive feedback, mechanism amplifies a … into a …
Positive feedback, mechanism amplifies a small change into a big change.
what anatomical adaptations does the liver have for increasing SA?
Liver has highly vascularised and lobular structure, give increased SA. Liver cells, called hepatocytes, have microvilli, further increase SA.
Ornithine cycle
process combining ammonia and carbon dioxide, form urea, much less toxic and soluble in water, so it can be excreted into the urine.
how have the renal tubules of each nephron adapted to become more efficient at reabsorption?
The renal tubule of each nephron, lined with microvilli, increase SA for reabsorption.
what happens during the process of Ultrafiltration
most blood forced out, into the glomerular capsule due to the high pressure caused by the difference in diameter between the afferent (much wider) and efferent arterioles.
In the nephron, at which parts is water and ions reabsorbed into the blood?
Water is also reabsorbed into the blood by osmosis in the descending limb of the loop of Henle. Ions reabsorbed in ascending limb.
The ion conc gradient set up in the area between the limbs drives osmosis in the descending limb.
How is ADH secreted?
Osmoreceptors in the hypothalamus detect water composition in the blood. Hypothalamus secretes ADH, and signals posterior pituitary gland to release it into the bloodstream.
how does ADH work, and what is the risk of a high conc of ADH?
When ADH reaches cells in collecting ducts, become more permeable to water, so reabsorb more water. High conc of ADH constrict blood vessels, increasing blood pressure.
Glomerular filtration rate (GFR) indicates what?
how well the kidneys are functioning and estimates the amount of blood passing through the kidneys per minute.
what does kidney failure effect?
the balance of electrolytes in the body.
what are the 2 types of dialysis?
Hemodialysis and Peritoneal dialysis
What happens to a plant of rate of photosynthesis is greater than rate of respiration?
If the rate of photosynthesis is greater than rate respiration, excess oxygen expelled out the plant, via diffusion.
how does the Iselt of Langerhans help to regulate blood glucose levels?
The islets of Langerhans, areas produce and secrete insulin and glucagon into the blood to help regulate blood glucose levels.
where are the substances for exocrine glands secreted into, and endocrine glands?
Exocrine glands secrete substances into ducts, endocrine into blood.
Amylase needs … to complete active site.
Cl- cofactor
