17.1-17.5 Flashcards
1
Q
Gene Expression
A
The process by which DNA directs the synthesis of proteins (or in some cases the RNAs)
2
Q
Stages of Gene expression
A
Transcription and Translation
3
Q
Examples of proteins that are not enzymes
A
Keratin and Insulin
4
Q
What is a primary transcript?
A
Initial RNA transcript from any gene, including those specifying RNA that is not translated into protein
5
Q
What is the central dogma
A
DNA–> RNA–> protein
6
Q
How many possible combinations can there be of amino acid code
A
4^3 = 64 possible combinations
7
Q
Which way do strands get read?
A
5’ –> 3’
8
Q
What does RNA polymerase do?
A
It pries two strands of DNA apart and joins together RNA nucleotides complementary to the DNA template strand.
9
Q
Initiation
A
RNA polymerase binds to promoter, DNA strands unwind, and polymerase initiates RNA synthesis at START POINT on template strand.
10
Q
Elongation
A
Polymerase moves downstream (after gene), unwinding DNA and elongating the RNA transcript 5’–> 3’. Also DNA strands re form a double helix
11
Q
Termination
A
Eventually, the RNA transcript is released and polymerase detaches from DNA.
12
Q
What is the promoter?
A
The DNA sequence where RNA polymerase attaches and initiates transcription
13
Q
Initiation promoter binding
A
RNA polymerase II must bind to the promoter AFTER transcription factors (bunch of protiens) bind to the promoter.
14
Q
What is a transcription initiation complex?
A
Complex of transcription factors, and RNA polymerase II bound to the promoter.
15
Q
Initiation in Eukaryotes `
A
In the PROMOTER, there is a TATA box (25 nucleotides upstream from the starting point-before)
The transcription factors RECOGNIZE the TATA box and bind before RNA polymerase II binds.
16
Q
Functions of the Poly-A tail and 5’ cap
A
- To facilitate export of mature mRNA from nucleus
- To help PROTECT mRNA form degredation by hydrolytic enzymes
- Help ribosomes attach to the 5’ end of mRNA once it reaches the cytoplasm
17
Q
snRNPs
A
‘snurps’ they recognize the splicing sites
made up of RNA and protein molecules
‘ small nuclear ribonucleoproteins’
They join with protiens to form a spliceosome
18
Q
What are ribozymes?
A
RNA molecules functioning as enzymes, Intron RNA functions as ribozyme and catlyises its own excision. Pre-rRNA removes its own introns.
e.g. protist Tetrahymena
19
Q
Alternative RNA splicing
A
Lots of genes giving rise to two or three different polypeptides dpeending on which segments are treated as exons during the RNA processing.
20
Q
Exon shuffling
A
introns increase probabilty of crossing over beween exonss of alleles in gene. (by providing more terrain for it ) Could lead to new combinations of protiens with new functions.
21
Q
Which enzyme matches the tRNA and amino acid?
A
Aminoacyl-tRNA synthetases
22
Q
P site
A
Holds the tRNA carrying the growing polypeptide chain
23
Q
A site
A
holds the tRNA carrying the next amino acid to be added to the chain
24
Q
E site
A
Exit site.
25
SRP
signal- recognition particle- brings the ribosome to a receptor protein built into the ER membrane.
26
A series of enzymes catalyse the reaction X -> Y -> Z -> A. Product 'A' binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. In this example, substance 'X' functions as:
a. a competitive inhibitor.
b. an intermediate.
c. an allosteric inhibitor.
d. a substrate.
e. a coenzyme
d. Substrate
27
The capsid of influenza virus is cloaked by a:
a. sheath
b. cell wall
c. repeating units of the capsomer
d. lipid envelop with embedded glycoprotein
e. viral envelopes of protomers and glycoprotien
d. lipid envelop with embedded glycoprotein
28
During the secretory phase of the menstrual cycle:
a. endometrial arteries and glands enlarge.
b. the corpus luteum secretes glycogen.
c. the corpus luteum secretes estradiol and progesterone.
d. the oocyte is most susceptible to fertilisation.
a. endometrial arteries and glands enlarge.
29
How does tropomyosin control the muscle contraction?
a. It binds with sodium ions
b. It acts as a bridge between actin and myosin
c. Changing its shape opens membrane calcium channels
d. It provides a site where ATP can be utilised
e. Its position changes, exposing myosin binding sites on the actin
e. Its position changes, exposing myosin binding sites on the actin
30
Bone tissue consists of __________ cells in a matrix of __________.
a. chondrocyte; calcium phosphate
b. osteoblast; myosin and actin
c. colagen; calcium phosphate
d. osteoblast; polysaccharide
e. osteoblast; collagen and calcium phosphate
e. osteoblast; collagen and calcium phosphate
31
When the concentration of glucose in the medium falls during catabolite activation:
a. the concentration of CAP rises.
b. the concentration of repressor rises.
c. the concentration of cAMP rises.
d. the concentration of RNA polymerase increases.
c. the concentration of cAMP rises.
32
In the fish circulatory system:
a. blood leaving the gills in under high pressure.
b. blood leaving the heart moves directly to body tissues.
c. blood moves from the muscular ventricle to the gills.
d. blood entering the heart is under high pressure.
c. blood moves from the muscular ventricle to the gills.
33
External _____are highly branched folds of the body surface that maximise gas exchange.
Gills
34
ES is called an "endocrine disrupting chemical" because it structurally resembles, and interferes with, the endocrine secretions of the
a. adrenal medulla
b. thyroid gland
c. hypothalamus
d. ovaries
e. pancreatic islet cells
d. ovaries
35
Through which one of these structures does urine enter the urinary bladder?
a. renal artery
b. urethra
c. ureter
d. renal medulla
e. convoluted tubule
ureter
36
Which one of the following structures is found in the inner renal medulla of the kidney?
a. Bowman's capsule
b. Loop of Henle
c. distal tubule
d. glomerulus
e. proximal tubule
Loop of Henle
37
When an operon is turned off in response to molecules present in the environment of the cell, it is:
a. impressible.
b. suppressible.
c. inducible.
d. repressible.
e. ostentatious.
Repressible
38
Bacillus cereus is a:
a. Gram negative rod.
b. Gram positive coccus.
c. Gram positive rod.
d. Gram negative coccus.
e. Gram negative spirelli.
Gram positive rod.
39
Typically, mammals do not use colourful displays when signalling other members of the species. This is unlike both birds and lizards, which use a lot of colourful displays during intraspecies interactions. Some mammals are quite brightly coloured, and possibly the lack of this behaviour in mammals is because most mammals are colour blind and have a long evolutionary history of having been colour blind. There is little point in displaying colours if none of the other members of the species can see in colour. Is this a proximate or ultimate explanation for the behaviour described?
Ultimate
40
A bacterium entering the body through a small cut in the skin will do which one of the following?
a. inactivate the hemocytes
b. stimulate apoptosis of body cells
c. activate a group of proteins called complement
d. stimulate release of interferons
e. stimulate natural killer cell activity
activate a group of proteins called complement
41
Cartilaginous fishes maintain an osmotic concentration in their blood that matches that of seawater by:
a. concentrating urea in their body fluids.
b. excreting large amounts of water.
c. drinking large amounts of seawater.
d. concentrating seawater salts in their blood.
e. excreting salt at their gills.
concentrating urea in their body fluids.
42
Conjugation in bacteria is mediated by
. Bacterial take up of plasmid DNA from the external environment
b. The expression of a sex pilus that joins the donor to the recipient
c. a bacteriophage injecting the donor
d. The the bacteria exchange of DNA and cellular organelles.
. The expression of a sex pilus that joins the donor to the recipient
43
The morphogenetic changes that occur during organogenesis include:
a. differentiation, totipotency and determination.
b. invagination, involution and migration.
c. cleavage, blastulation and gastrulation.
d. folds, splits and condensation of cells.
folds, splits and condensation of cells.
44
Which one of the following is NOT a function of the excretory system?
a. Elimination of undigested food
b. Elimination of nitrogenous wastes.
c. Maintenance of salt balance.
d. Maintenance of water balance
e. Production of urine.
Elimination of undigested food
45
Which primary germ layer gives rise to the cells that make up the neural tube?
a. blastomere
b. mesoderm
c. ectoderm
d. endoderm
e. periderm
Ectoderm
46
What does bacterial mating involve?
a. exchange of egg and sperm
b. formation of a conjugation tube for the transfer of male DNA
c. sex pili that draw the cells together so mRNA can be inserted
d. integration of male and female DNA into a conjugation tube
e. binary fission of a bacterial cell
formation of a conjugation tube for the transfer of male DNA
47
Which one of the following statements about the pulmonary circuit is FALSE?
a. In birds and mammals, the major disadvantage of the pulmonary circuit is that mixing of oxygenated and de-oxygenated blood occurs in the heart.
b. Blood is pumped through the pulmonary circuit at a much lower pressure than through the systemic circuit.
c. Cutaneous respiration in amphibians compensates for mixing of pulmonary and systemic blood.
d. Fish lack distinct systemic and pulmonary circulatory systems.
In birds and mammals, the major disadvantage of the pulmonary circuit is that mixing of oxygenated and de-oxygenated blood occurs in the heart.
48
In the human heart, blood is pumped from the left ventricle into the:
a. left atrium.
b. right atrium.
c. right ventricle.
d. systemic circuit.
e. pulmonary circuit.
Systemic Circuit
49
A resting potential is different from an action potential in that:
there is no net charge across the membrane when it is at resting potential.
b. all of the gated channels are closed when a membrane is at resting potential.
c. the membrane is depolarised when it is at resting potential.
d. when the membrane is at resting potential it is impermeable to charged ions.
. all of the gated channels are closed when a membrane is at resting potential.
50
Birds and mammals are able to produce a hyperosmotic urine through modification of which structure?
a. Bowman's capsule
b. renal medulla and cortex
c. collecting ducts
d. loop of Henle
e. proximal convoluted tubule
loop of Henle
51
During catabolite conversion, the CRP must first bind to:
a. the repressor molecule.
b. cAMP
c. glucose
d. the promoter region.
e. the activator protein.
cAMP
52
The typical reptilian heart is distinguished from the amphibian heart by the presence of:
a. two separate atria.
b. a partially divided ventricle.
c. systemic and pulmonary circulation.
d. two separate ventricles.
e. cutaneous respiration.
a partially divided ventricle.
53
For an animal that is already moving, which is the most metabolically expensive mode of locomotion?
a. Swimming
b. Undulatory movement (e.g. 'slithering' in snakes)
c. Flying
d. Running
Running
54
Which one of the following BEST characterises the lungs of mammals?
a. crosscurrent flow
b. complete emptying during during exhalation
c. countercurrent air flow
d. tidal volume system
e. joined with air sacs
Tidal volume system
55
The vehicle that is used to insert foreign DNA into a host is broadly known as a ______
Plasmid
56
Which step in the Gram staining process will give you the initial difference between Gram positive and Gram negative?
a. Alcohol
b. Crystal violet
c. Carbol fuschin
d. Grams Iodine
Alcohol
57
Synaptic integration is
a. the process of the membrane potential being kept below threshold at the postsynaptic neuron.
b. the sum of of the effects of excitatory and inhibitory postsynaptic potentials.
c. the propagation of action potentials at neuromuscular junctions.
d. the transmission of nervous impulses as controlled by the brain.
the sum of of the effects of excitatory and inhibitory postsynaptic potentials.
58
Specific amino acids are attached to tRNA molecules by:
a. synthetase enzymes.
b. codons.
c. initiation factors.
d. ribosomes.
e. anticodons.
Synthetase enzymes
59
Which one of the following statements about the ovary is FALSE?
a. A follicle consists of one egg cell and the surrounding follicle cells.
b. Apart from producing eggs, the ovary also acts as a gland.
c. Follicle development is stimulated by the action of hormones.
d. At any point in time, there is ONLY one folicle developing.
At any point in time, there is only one folicle developing
60
The part of the testis that produces the male sex hormones is the:
a. vas deferens
b. epididymis.
c. seminiferous tubules.
d. scrotum.
e. Leydig cells.
Leydig cells
61
Escherichia coli is a:
a. Gram negative rod
b. Gram positive coccus
c. Gram negative coccus
d. Gram positive rod
Gram negative rod
62
Brown fat is a body tissue type in some mammals that is specialised for:
a. energy storage for hibernation.
b. maintaining the shivering stimulus.
c. countercurrent heat exchange.
d. rapid heat production.
rapid heat production.
63
During the evolution of animals, major changes in the mechanism of external respiration have tended to maximise the rate of diffusion by favoring changes that:
a. decrease the distance across the membrane.
b. increase the surface area.
c. use all of, or any combination of, these options.
d. increase the concentration difference of gases across the membrane.
Use all of, or any combination of, these options
64
Bone is harder than cartilage, but not brittle, because:
a. it combines hard mineral with flexible collagen.
b. the interior of bone is spongy.
c. osteocytes are located in lacunae.
d. the inside of bone is filed with bone marrow
e. it possesses a greater number of cells within the matrix.
It combines hard material with flexible collagen
65
An animal that eats poisonous fruit that causes the animal to be sick will learn to recognise the fruit's colour, shape and smell, and thereafter, it will avoid eating the fruit again. Is this a proximate or ultimate explanation for the behaviour described?
Select one:
Proximate or Ultimate
Proximate
66
In mammals, the first cleavage division is completed approximately _______ after fertilization.
a. 15 minutes
b. 12 hours
c. 36 hours
d. 6 hours
e. 90 minutes
36 hours
67
Which one of the following statements is FALSE?
a. Arthropods have a single digestive chamber, the cecum, in which all digestion occurs.
b. The organs of the gastrointestinal tract are multilayered.
c. Malnourishment can occur when animals have a nutrient deficiency even though they are getting enough energy from their food.
d. Different animal species may require different essential amino acids.
Arthropods have a single digestive chamber, the cecum, in which all digestion occurs
68
Glial cells that encircle brain capillaries, restricting the passage of substances in the brain, contribute to what is known as the:
a. postsynaptic membrane.
b. toxin recognition system.
c. presynaptic membrane.
d. blood-brain barrier.
e. autonomic nervous system.
Blood-brain barrier
69
Exoskeletons provide:
a. A place to tether muscles for doing work only
b. Protection and a place to tether muscles for doing work
c. Protection only
Protection and a place to tether muscles for doing work
70
Mammalian blood cells that lack a nucleus and have a relatively short life span are:
a. erythrocytes.
b. lymphocytes.
c. neutrophils.
d. basophils.
e. eosinophils.
Erythrocytes
71
Which one of the following statements is INCORRECT? The intestinal microflora
a. is involved in the synthesis of many important vitamins.
b. consists primarily of acid tolerant rods (bacilli) along the length of the gastrointestinal tract.
c. may have different compositions within and between hosts.
d. have different community compositions along the gastrointestinal tract.
consists primarily of acid tolerant rods (bacilli) along the length of the gastrointestinal tract.
72
Why would evaporative cooling be used only as a last resort by animals living in hot, dry habitats?
a. evaporative cooling requires an insulating layer in the skin.
b. evaporative cooling is ineffectve at dissipating heat.
c. sweating requires little energy expenditure.
d. water is usually a limiting resource in such habitats.
Water is usually a limiting source in such habitats
73
Which is the correct sequence of events?
Select one:
a. Action potential arrives at muscle cell -> muscle cell membrane depolarises -> depolarisation moves into the interior of the cell via T tubules -> tropomyosin moves, revealing myosin binding sites on the actin molecule -> calcium ions are released from sarcoplasmic reticulum
b. Action potential arrives at muscle cell -> muscle cell membrane depolarises -> depolarisation moves into the interior of the cell via T tubules -> tropomyosin moves, revealing myosin binding sites on the actin molecule -> sodium ions are released from sarcoplasmic reticulum
c. Action potential arrives at muscle cell -> depolarisation moves into the interior of the cell via T tubules -> muscle cell membrane depolarises -> tropomyosin moves, revealing myosin binding sites on the actin molecule -> calcium ions are released from sarcoplasmic reticulum
d. Action potential arrives at muscle cell -> muscle cell membrane depolarises -> depolarisation moves into the interior of the cell via T tubules -> calcium ions are released from sarcoplasmic reticulum -> tropomyosin moves, revealing myosin binding sites on the actin molecule
e. Action potential arrives at muscle cell -> muscle cell membrane depolarises -> depolarisation moves into the interior of the cell via T tubules -> tropomyosin moves, revealing myosin binding sites on the actin molecule -> potassium ions are released from sarcoplasmic reticulum
Action potential arrives at muscle cell -> muscle cell membrane depolarises -> depolarisation moves into the interior of the cell via T tubules -> calcium ions are released from sarcoplasmic reticulum -> tropomyosin moves, revealing myosin binding sites on the actin molecule
74
At the moment of sperm penetration, human eggs
a. are still located within the ovary
b. have a paper-thin cell of calcium carbonate that prevents desiccation
c. have used flagellar propulsion to move from the ovary to the oviduct
d. are still surrounded by follicular cells
e. accept as many sperm as possible in order to select the one with the highest fertility
are still surrounded by follicular cells
75
The bacterium that causes anthrax is:
a. Gram positive coccus.
b. Gram negative rod.
c. Gram positive rod.
d. Gram negative coccus.
e. Gram negative spirelli.
Gram positive rod
76
In humans, the breathing control centres are located in two regions of the brain, the medulla oblongata and the ______.
Pons. It controls breathing and communication between different parts of the brain.
77
Regulator
Animal that uses internal mechanisms to control the internal change in the face of external fluctuation
78
Conformer
Animal that changes its internal state with the change in the external environmental variable
79
Circadian rhythm
Set of physiological changes that occur roughly every 24 hours. e.g. body temperature rising and falling more than 0.6 degrees in every 24 hour period.
80
Acclimatisation
normal range of homoeostasis changes through a gradual process(animal adjusts to changes in its external environment)
81
Poikiotherm
Animal whose body temperature varies with its environment
82
Homeotherm
Animal that has a relatively constant body temperature
83
Are all ectotherms poikithermic?
NO not necessarily! For example there are fishes that inhabit water that has such stable temperatures that it doesn't fluctuate compared to an endotherm who could have a bigger fluctuation due to environment.
