OU - BIO - 1124
Final Exam Study Guide
105 Things To Know
1. Gene- Discrete unit of hereditary information in a specific nucleotide sequence Chromatin- Complex of DNA and protein that make up a chromosome 2. Template strand of DNA- The strand which is translated and provides the sequence of nucleotides for the RNA transcript
3. Overview of Eukaryotic protein synthesis
a. DNA sequence > transcription (in nucleus) > Pre-mRNA > mRNA processing (in nucleus) > mRNA sequence > translation (at ribosome) > protein
4. Transcription- The synthesis of mRNA using a DNA template
5. Gene expression- Process by which information encoded in DNA directs the synthesis of proteins
1. Transcription factors- A regulatory protein that binds to DNA and affects transcription of specific genes
2. RNA transcript- The sequence of nucleotides transcribed from the template DNA by an RNA polymerase We also discuss several other topics like What refers to the situation where the consumers shop offline to get a feel of the product then buy the product online at a cheaper price?
3. RNA polymerase- The enzyme that accomplishes transcription and separates the DNA so that a RNA transcript can be copied
4. Pre-mRNA- The "Primary transcript" of RNA copied from the DNA template which requires further processing before leaving the nucleus
5. Exons- Regions of the pre-mRNA transcript that will be translated and expressed 6. Introns- mRNA sequences that are not translated and must be spliced out of the pre-mRNA We also discuss several other topics like What is the meaning of protein quality?
7. In the process of protein synthesis, what is the purpose of transcription? a. Transcription builds a strand of pre-mRNA from the DNA template strand b. This pre-mRNA strand will be eventually used to synthesize proteins 8. What is the purpose of transcription factors in transcription?
a. Transcription factors bind to the DNA at the promoter region (the start of the desired gene) and give the target binding area for the RNA
9. What are the two categories of RNA processing in protein synthesis? a. Alteration of mRNA ends
b. RNA splicing
10.How are each of the two ends of pre-mRNA altered before the pre-mRNA leaves the nucleus?
a. At the 5' end, a modified guanine nucleotide is added called the "5' - cap"
b. At the 3' end, a "poly-a tail" of repeated adenine nucleotides is added 11.Why is alteration of pre-mRNA ends needed (two reasons)? a. Alteration facilitates (1) movement of RNA out of nucleus, and (2) attachment of mRNA to ribosomes in the cytoplasm
12.What is mRNA splicing?
a. The removal of long sequences of RNA that is not translated 13.What are two functions of introns?
a. Regulate expression of the gene (function in process of turning genes on and off) If you want to learn more check out What is the definition of water resources?
b. Alternative splicing of RNA : one gene may be translated into different proteins, depending on which regions of the pre-mRNA are spliced 14.Codon- A three nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; basic unit of genetic code If you want to learn more check out What is the meaning of phospholipid bilayers?
15. AntiCodon- A nucleotide triplet at one end of a tRNA molecule that base-pairs with a particular complementary codon on an mRNA molecule
16.Transfer RNA (tRNA)- transfers an amino acid in the cytoplasm to a ribosome to build a Polypeptide
a. RNA molecule of about 80 nucleotides in length
17.In interpreting codons in mRNA, what is the directionality of encoded information?
a. Codons are read 5' > 3'
18.Overall function of translation?
a. Translation converts the mRNA code into an actual amino acid sequence to form a protein
19.Draw the tRNA molecule and label
a. If you want to learn more check out Species richness refers to what?
20.Homeostasis- Maintenance of an appropriate internal environment of the body - often a "Steady-state" environment Don't forget about the age old question of What is the numerical summary of a population?
21.What is the basic structure of a ribosome?
a. Made up of two subunits of Ribosomal RNA (rRNA) and proteins 22.Where are ribosomes themselves synthesized?
a. Ribosomes are synthesized in the nucleus
23.What are the nucleic acid molecules that come together at a ribosome to carry out protein synthesis?
a. mRNA and aminoacyl-tRNA
24.What are the three tRNA binding sites in a ribosome?
iii. Aminoacyl - tRNA
25.How is translation terminated?
a. Occurs when a "stop" codon in mRNA reaches the A site
b. Stop codons are UAA, UAG, and UGA
26.Following translation, what two modifications may be made to polypeptides to make it a functional protein
a. 1. Protein folding to form correct secondary and tertiary structure b. 2. Post-translational modifications - e.x. adding a carbohydrate to make a glycoprotein
27.Draw a ribosome in which translation is occuring
a. 28.What is the role of insulin in regulation of blood glucose levels? a. Triggers uptake of glucose from blood into cells of the body, so blood glucose level decreases
29.What is the role of glucagon in regulation of blood glucose levels? a. Triggers release of glucose into the blood from stores in the liver, so blood glucose level increases
30.Why are insulin and glucagon called antagonistic hormones? a. They don't "like" each other ; one decreases blood glucose level while the other increases, so they conflict
31.Why are antagonistic hormones helpful in maintaining homeostasis? a. Because they can increase or decrease the level of a substance in order to stay within a desired range
32.Where exactly are glucagon and insulin produced in the human body? a. Insulin and glucagon are produced in the pancreas by clusters of endocrine cells called islets
33.What hormone is produced in the alpha cells of the pancreas? a. Glucagon
34.What hormone is produced in the beta cells of the pancreas? a. Insulin
35.What are the two causes of diabetes mellitus?
a. Deficiency of insulin production or
b. Decreased response to insulin by target cells
36.What are two physiological consequences of untreated diabetes? a. Cells don't take up enough glucose for cellular respiration so fats become main substrate for respiration
b. Excess glucose is excreted in urine, and large amounts of water are excreted along w/ glucose due to disrupted osmoregulation
37.What is type 1 diabetes, and how is it treated?
a. Autoimmune disorder in which the immune system destroys the insulin producing cells of the pancreas
b. Onset in childhood
c. Treated with insulin injections
38.What is type 2 diabetes, and how is it treated?
a. Insulin receptors on body cells don't respond to insulin and cells fail to take up glucose
b. Onset usually after 40
c. Treatment is a healthy diet and exercise, and sometimes medications 39.Osmolarity- Moles of total solutes per solution
a. Measure of the "Concentration of solutes in water"
40.Osmoregulation- Regulation of solute concentrations and water balance by a cell or organism
41.Semipermeable membrane- Membrane that water can move through freely but solutes can't
42.Isotonic- Both sides of a semipermeable membrane have the same osmolarity a. Water moves across the membrane but there is no net change in concentration of solutes
43.Hyperosmotic- Higher solute concentration on one side of the membrane 44.Hypoosmotic- Lower solute concentration on one side of the membrane 45.Where does water move in a solution with a hypo and hyper osmotic sides? a. Water always moves towards higher solute concentration
b. Thus water moves towards the hyperosmotic side
46.Osmoconformer- Organisms that are iso-osmotic with their environment 47.Osmoregulator- Organisms that control internal osmolarity independent of their environment
48.Stenohaline- Animals that can't survive large changes in the osmolarity of their environment
49.Euryhaline- Animals that have adaptations for dealing w/ changes in the osmolarity of their environment
50.What is an osmoconformer, and where do you expect to find one? What are some examples?
a. Animals that are iso-osmotic with their environment
b. Animals found in marine (ocean) environments that are stable c. E.x. Corals, other marine invertebrates
51.What is an osmoregulator, and where do you expect to find one? What are some examples?
a. Animals that can control internal osmolarity
b. Animals found in freshwater, terrestrial environments
c. E.x. Most freshwater and marine fish (trout), mammals (human)
52.Draw solutions separated by a semipermeable membrane
a. 53.Transport epithelium- Specialized epithelial cells that carry out and regulate solute and water movement
a. Involved in osmoregulation and excretion
b. Move specific solutes in controlled amounts in specific directions 54.Interstitial fluids- Fluids filling the spaces between cells in animals a. Affects osmolarity of cells
55.For land animals, what is the major osmoregulatory challenge? a. Dehydration (loss of water) is the major challenge
56.How do land animals cope with their osmoregulatory challenge? a. Body coverings resists loss of water (skin)
b. Animals drink water
c. Some use metabolic water (H2O from cellular respiration)
57.What is metabolic water, and what animals rely on it as a major source of their water?
a. Water derived from cellular respiration
b. Animals in very arid (dry) environments such as the kangaroo rat 58.Why do animals need to excrete nitrogenous waste?
a. Animals typically consume more nitrogen than they need
b. Excess nitrogen breaks down into Ammonia and Ammonium - both are toxic
c. Animals thus excrete nitrogenous waste to reduce toxicity
59.What is the natural breakdown product of nitrogenous molecules consumed in an animal's diet?
a. Nitrogen will breakdown into Ammonia (NH3) then Ammonium (NH4) 60.Why are ammonia and ammonium problematic as excretory products in some animals?
a. They are both toxic
61.What are the three kinds of excretory products found among animals? a. Ammonia, Urea, or Uric acid
62.What are the benefits of excreting ammonia, and what are the downsides? a. Benefits
i. Highly soluble, so diffuses readily across membranes and out of body
ii. Does not require energy to produce
i. Extremely toxic
63.What is an example of an animal that excretes ammonia?
a. Animals with access to lots of water like fish
b. Excrete it across their gills
64.What are the benefits of excreting urea, and what are the downsides? a. Benefits
i. Soluble, low toxicity
ii. Can be concentrated in a solution, so conserves water
i. Energy is required to (1) Build Urea, and (2) concentrate it in urine 65.What is an example of an animal that excretes urea?
a. Terrestrial animals excrete urea in urine
i. Ex: Humans
66.What are the benefits of excreting uric acid, and what are the downsides? a. Benefits
i. Has very low toxicity
ii. Very little water loss
i. Extremely expensive to produce
67.What is an example of an animal that excretes uric acid?
a. Animals that have very little access to water such as insects, birds, reptiles
68.Nephron- Tubular excretory unit of the kidney
a. Has the loop of Henle as well as capillaries
69.In excretory systems, what is the process of filtration?
a. Water, solutes, including waste, is forced out of a cluster of capillaries into the Bowman's capsule by blood pressure
70.In excretory systems, what is the process of reabsorption?
a. Transport epithelium removes valuable substances from filtrate and returns them to the blood (e.g glucose, nutrients, water)
71.In excretory systems, what is the process of secretion?
a. Toxins and excess ions are extracted from blood and added to excretory tube by active transport
b. During reabsorption, what kinds of substances are reabsorbed c. Glucose, hormones, vitamins, H2O
72.During secretion, what kinds of substances are secreted?
a. Toxins and excess ions
73.In a human nephron, where does filtration occur?
a. In the bowman's capsule as blood pressure forces fluid from the glomerulus into the bowman's capsule
74.In a human nephron, what causes blood fluid to be forced into the bowman's capsule?
a. Blood pressure
75.In the bowman's capsule, what does the initial filtrate contain? a. Nitrogenous waste, Salt, amino acids, glucose, vitamins, and other small molecules
76.Why is it important that urea is 60-times greater in urine than it is in the body? a. The kidney concentrates urea in urine so that water may be conserved, and so that the toxic urea may be excreted
77.What trick does the kidney use to concentrates solutes, like urea, in the urine?
a. Creates and maintains a hyperosmotic environment in the renal medulla using active transport of NaCl
b. This allows water to escape the urine and diffuse into the renal medulla by osmosis
78.What are the two kinds of nephrons present in the human kidney, and how do they differ?
a. Cortical nephrons and Juxtamedullary nephrons
b. Cortical nephrons have short loops of Henle and are in the renal cortex c. Juxtamedullary nephrons have loops of Henle which extend deep into the medulla and allow urine to be concentrated
79.In a human nephron, what two processes occur during secretion in the proximal tubule?
a. Toxic substances are actively transported from peritubular capillaries to the excretory tube
b. Secretion of certain ions and molecules into the excretory tube for regulating correct pH of 7.4 in the body
80.What structures in the kidney regulate pH?
a. Proximal and distal tubule regulate pH to maintain a pH of 7.4 81.In the descending loop of Henle, what is the composition of membrane-bound transport proteins?
a. Mainly made of aquaporins, allows H2O to be reabsorbed by the capillaries
b. No ion channels, so no salt leaves excretory tube
c. "Water spigot is on full blast"
82.How does the composition of membrane bound transport proteins in the descending limb of the loop of Henle shape the function of the descending limb? a. Because there are so many aquaporins, the descending limb functions in the reabsorption of water by the capillaries
83.In the descending loop of Henle, why does osmolarity of the filtrate increase as it moves down into the inner medulla?
a. Because water is diffusing out of the filtrate by osmosis, so there is a higher concentration of solutes left behind as it goes deeper into the medulla
84.In the ascending loop of Henle, what is the composition of the membrane bound transport proteins?
a. Contains many ion channels, but no aquaporins
b. "Ion spigot is on full blast"
85.How does the composition of membrane bound transport proteins in the ascending loop of Henle shape the function of the ascending limb?
a. Because ions are moving out of the ascending limb through ion channels, a high concentration of NaCL is maintained in the medulla
b. Maintains the high osmolarity of the medulla needed for water osmosis 86.In the ascending limb of the loop of Henle in the inner medulla, what substances diffuses from the filtrate into the interstitial fluid?
a. NaCl (salt)
87.In the ascending limb of the loop of Henle in the outer medulla, what substance is actively transported from the filtrate into the interstitial fluid?
a. NaCl (salt)
88.In the ascending limb of the loop of Henle, why does NaCL diffuse from the filtrate into interstitial fluid in the inner medulla, but is actively transported in the outer medulla?
a. In in the inner medulla, salt is highly concentrated in the ascending limb so it follows its concentration gradient out into the inner medulla passively b. In the outer medulla, salt isn't concentrated higher in the limb than outside of it, so it must be actively transported against its concentration gradient
89.In the loop of Henle, what specific process requires much energy expenditure (in the form of ATP)?
a. The active transport of NaCl out of the excretory tube and into the outer medulla
90.What are three functions of the loop of Henle?
a. Removes water from filtrate
b. Removes NaCl from filtrate
c. Creates the osmolarity gradient that allows concentration of urea in urine 91.Antidiuretic Hormone- Primary osmoregulatory hormone in mammals a. Produced in the hypothalamus, stored in the pituitary gland
92.Osmoreceptor cells of the hypothalamus- Detect osmolarity of the blood a. Regulated release of ADH into the blood
93.In the mammalian nephron, what are two functions of the distal tubule? a. Regulation of K and NaCl concentrations in body fluids
b. Regulation of pH in body tissues
94.What is the function of the collecting duct?
a. Final step that concentrates urea and other solutes in the urea 95.What role do hormones play in osmoregulation in the collecting duct? a. Hormones control the degree to which collecting ducts concentrate urine 96.In the collecting duct what osmoregulatory mechanism occurs when the body is dehydrated and needs to conserve water?
a. Aquaporins are added and more H2O diffuses out into the body tissues
97.In the collecting duct, what osmoregulatory mechanism occurs when there is excess water in the body?
a. Aquaporins are removed and more water is retained in the collecting duct, making the urine more dilute
98.What body organ performs osmoregulation in animals?
99.Where is antidiuretic hormone (ADH) produced and stored? a. Produced in the hypothalamus and stored in the pituitary gland