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222 Cards in this Set
- Front
- Back
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Events as RNA is synthesized from DNA and then proteins are synthesized from RNA
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1. DNA template is made from a strand of DNA
2. mRNA is synthesized from DNA template strand 3. Ribosomes are involved in translation 4. tRNAs charged with amino acids get involved in the actual peptide formation in the ribosome |
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DNA forms a
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double helix of two anti-parallel strands
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During transcription the template DNA is read
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from 3' to 5' end
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Chargaff's rule
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the number of purines is always equal to the number of pyramidines
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A sequence of 3 RNA bases
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Codon or anticodon; not a gene
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At contact, the codon and anticodon are
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antiparallel
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Lipids are
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1. important for energy storage
2. hydrophobic 3. Insoluble in water 4. important constituents in biological membranes |
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Phospholipids
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contain a phosphoric acid molecule attached to the third OH group in the fatty acids
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A fat contains
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fatty acids and glycerol
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Triglycerides are synthesized
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from fatty acids and glycerol
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Pentose
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A simple sugar with the formula C5H10O5
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Glycosidic
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The bonds that link sugar monomers in starch molecules
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Condensation reactions can produce
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Polysaccharides, polypeptides, triglycerides
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5'ACGGTACGTAAGC3'
would be transcribed to |
UGCCAUGCAUUCG
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What is the nucleotide sequence of the complementary strand of the DNA molecule: AATGCGA
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T T A C G C T
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The sodium/potassium pump results in
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the formation of a membrane potential across the plasma membrane
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The first component in signal transduction is always
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a receptor
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In order, from start to finish, the basic steps of a signal transduction pathway are
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signal, receptor, responder, effects
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Calcium ions
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can act as secondary messengers
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Epinephrine receptor an example of
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a G protein linked receptor
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Calmoldulin
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a calcium binding molecule
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Ligand
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A molecule that binds to a receptor site in another molecule
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Inositol Triphosphate
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a secondary messenger
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Secondary messengers
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can be derived from lipids
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Phosphorylation of a protein
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often the final step in signaling
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Support
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a common function of stems but not roots
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Node
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The point where a leaf attaches to a stem
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Tracheids, vessel elements, and sclereids
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all function when they are dead
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Adventitious root
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originates from the stem
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Epidermis
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the outer layer of cells that protects a plant
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Meristem
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undifferentiated cells that develop and grow outward to replace dead cells
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The developmental sequence of a root cell
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division, elongation, differentiation
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Stomata begin to open when K+ ions
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becomes concentrated, water enters guard cells, and the cells become turgid
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To initiate stomatal opening, K+ ions
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are driven into guard cells by a charge gradient.
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The opening and closing of the stomata are accomplished by
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guard cells
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The opening of stomata in the light involves
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facilitated diffusion of K+ into guard cells
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Ψp = -2T/r (water potential)
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T is surface tension and r is the radius of curvature
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Pure water under no applied pressure has a water potential of
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0
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When turgor pressure is low
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plant tissue wilts
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Auxins are plant hormones that affect
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Root initiation
Apical dominance Leaf abscission Cell expansion |
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The discovery of auxin can be traced back to the work of Charles and Francis Darwin and their studies of -
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Phototropism
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Polar movement of auxin means -
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Auxin is is transported from the tip to the base of the plant.
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Chemically auxin is
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Indole Acetic Acid
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The likely result of treating a shoot cutting with auxin would be
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Extensive root production
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After the end of mitosis, the number of daughter cells formed from one parent cell is ___ and the ploidy of cells is ___ if the ploidy of the parent is 2n
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2;2n
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In the fertilization of almost all angiosperms, the two _______ sperm nuclei first enter the cytoplasm of a _______ synergid cell. One sperm nucleus fuses with the nucleus of the egg to produce a _______ zygote, and the other sperm nucleus fuses two polar nuclei to produce a _______ endosperm.
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haploid; haploid; diploid; triploid.
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Pollen
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the gametophyte of a flowering plant
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Megagametophyte
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Another name for the embryo sac in a flowering plant
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Growing pollen tubes
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Maintain a tip-high intracellular Ca2+ gradient.
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2 sperm nuclei fertilise
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One egg nucleus and two polar nuclei
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The megasporocyte divides
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Meiotically to produce four haploid cells, one of which becomes the haploid megagametophyte.
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Antipodal cells
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Do not fuse with any nuclei in the fertilisation process
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In mammals, the species-specific mechanism by which egg and sperm recognize one another is found in the
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zona pellucida
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The order of events for fertlization of asea urchin egg with sperm
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1: Chemotaxis
2: Acrosome reaction 3: Sperm egg adhesion 4: Plasma membrane contact 5: Gamete fusion |
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When a sea urchin egg (diameter 100 μm) divides into two blastomeres, both blastomeres are spherical and contain half of the original volume. What is the radius in micrometers of each blastomere?
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40 micrometers
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Important differences between sperm and eggs
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1. whether they are motile or not.
2. whether or not a protective layer exists outside the plasma membrane. 3. the amount of cytoplasm in them. 4. their size. |
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Salt water contains about 3.5% (3.5 gram salt in 100 mL water) of dissolved salts mostly comprising of Sodium chloride or NaCl. If the Na ions are removed from sea water, which of the following will happen with regards to fertilisation in sea urchins?
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polyspermy will occur and membrane potential of egg of sea urchin will not depolarise
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Bindin
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Covers the acrosomal process
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If a mutation was discovered in sea urchins that caused them to produce eggs with an overly dense vitelline envelope
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then normal sperm would fail to fertilise the eggs.
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The 2 blocks to polyspermy are caused by
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1. the membranes of the sperm and egg fusing
2. the entry of the sperm into the egg |
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The slow (permanent) block to polyspermy in the egg involves:
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1.Release of Ca2+
2. Osmotic influx of water into space between vitelline envelope and plasma membrane. 3.Breaking of bonds attaching the vitelline envelope to the plasma membrane. 4. Exocytosis of cortical vesicles |
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If you alter cells that are lining the archenteron in a developing vertebrate, such as a frog
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you could affect the digestive tract, respiratory tract, pancreas, or liver.
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The formation of the endoderm during gastrulation in frogs results
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from movement of cells from the surface layer to the interior
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Invagination of the sea urchin blastula is due to
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the uneven distribution of various transcriptional regulatory proteins in the egg cytoplasm
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The ratio of nuclear volume to cytoplasmic volume during the cleavage stage of development; at the same time the size of the blastomeres
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increases;decreases
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During cleavage, the cytoplasm of new cells in a developing frog embryo
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comes from the egg cytoplasm
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Micromeres
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Vegetal pole product of fourth cleavage in sea urchin embryos
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Blastula
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A hollow ball of cells with a fluid filled cavity formed early in embryonic development
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Blastocoel
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Fluid filled cavity in animal embryos
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Gray crescent
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Region formed by the rotation of the cortical cytoplasm in the frog zygote that is opposite the site of sperm penetration
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Epilblast
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The structure from which the embryo is derived in mammals and birds
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The movement of cells toward the blastopore
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epiboly
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In reptiles and birds includes a thickening called Hensen’s node, is similar to the dorsal lip of an amphibian blastopore. Both contain
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signaling molecules that organize the developing embryo
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If the dorsal lip of the blastopore from one gastrula was transplanted into the presumptive belly area of a second gastrula
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another complete embryo will form attached to the first embryo
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Mesoderm forms
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heart, blood vessels, muscle, and bones
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Endoderm forms
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post gastrulation development of lining of the digestive and respiratory tracts
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Ectoderm forms
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development of brain, nervous system, and sweat glands post gastrulation
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The primary mesenchyme gives rise to
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the mesoderm
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The point of sperm entrance in the egg
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is an important coordinate for developing frogs
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Cleavage
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The earliest stage of development
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Gastrulation
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makes possible the inductive interactions that trigger differentiation and organ formation
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Blastopore
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determines the anterior–posterior axis of the embryo.
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Bicoid proteins
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1. In a fertilised drosohila embryo, the bicoid protein enters the nucleus
2.Bicoid protein reaches a sharp threshold of concentration necessary to activate the hunchback gene 3.Transcription of the hunchback gene is activated |
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primary induction
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when the notochord sends a signal to the ectoderm, and causes it to form a neural plate and this process is called
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Correct sequence of neural developmental events
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1. Thickening of the neural ectoderm
2. Movement of the neural folds 3. Formation of the neural tube |
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The vertebral column
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is derived, via the notochord, from chordamesoderm
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Peripheral nerves
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are derived from the neural crest
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Action potentials are generated in a mechanoreceptor when
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ion channels open in response to membrane distortion
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After a neuron fires an action potential, there is a brief period, called the refractory period, during which it is impossible to cause another action potential to be produced. This is due to the inactivation of the
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Sodium channels
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Multinucleanated muscle
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skeletal muscle
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Muscle type which use calcium to trigger actin–myosin interactions for movement
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all three types of muscle
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Muscles with gap junctions
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smooth and cardiac muscles
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After the arrival of an action potential at the neuromuscular junction
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1: An action potential travels down the T tubules
3: Calcium is released from the sarcoplasmic reticulum 2: Depolarization spreads through the T tubule 4: Myosin binds actin |
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Saltatory conduction
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action potentials spread from node to node down the axon
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Synapse
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the site where one axon meets another cell
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Spatial Summation
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A postsynaptic cell’s processing of information from synapses at different sites
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Rhodopsin
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the basis for photosensitivity
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Partial pressure of oxygen
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PO2
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Surface tension
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P=2T/r
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Hemoglobin can combine with
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4 molecules of oxygen
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rhodopsin
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the molecule that is the basis for photosensitivity
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An increase in the binding rate of hemoglobin
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increases the amount of oxygen diffusing from the lungs into the blood
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Hemoglobin delivers O2 to body cells from the red bloods cells until
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until the partial pressures of O2 in the cells are the same
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Cells in the visual cortex
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respond to receptive field on the retina
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The receptive field of the retinal ganglion cell
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depends on the connections of horizontal and bipolar cells
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Membrane potential changes in the network of retinal cells
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activate ganglion cells
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Ganglion cell layers of the retina
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produce action potentials that are sent to the brain
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ON-bipolars
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depolarize ganglion cells and increase rate of action potentials
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The receptive field of the cells
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the area of the photoreceptors to which it responds
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Gap junctions
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allow large numbers of cardiac muscles to contract in unison
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The blood pressure is at a maximum when
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the ventricles are contracting during systole
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Sequence for the action potential passing through the heart
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1. SA node
2. Atrial Fibers 3. AV node 4. Bundle of His 5. Purkinje fibers |
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the pacemaker action potentials in the heart
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due to the spontaneous depolarization of the plasma membrane of modified cardiac muscle cells
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The AV node
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controls the timing of the spread of the action potential from the atrium to the ventricle
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sympathetic stimulation by norepinephrine increases the rate of the pacemaker
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speeds conduction of the action potential through the conducting tissue
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medulla
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the neural control of breathing
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G-protein coupled receptors
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have 7 transmembrane segments, transfer information to g-proteins
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The "G" in g-proteins
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binds to GTP and hydrolyze it to GDP
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Gs
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when activated leads to an increase in cAMP
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cAMP activates
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protein kinase A
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PKA (protein kinase A)
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catalyzes phosphorylation of ATP (transfer of a phosphate to another molecule, usually a protein)
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3 amino acids that can be phosphorylated
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serine, threonine, tyrosine
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kinases
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add phosphates
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phosphatases
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remove phosphates
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Acids
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release H+ into solution
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Base
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accepts H+ ions
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Synthesis of lagging DNA strand
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Primase adds RNA primer, DNA polymerase III creates stretch, DNA polymerase I removes the primer, ligase seals the gap
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reversible
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a chemical reaction that can proceed in either direction
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DNA polymerases
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function to replicate DNA in the cell
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3'
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The end that new monomers are added to during replication
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R-group
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what makes each amino acid unique
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Why is RNA incorporated into DNA replication?
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DNA polymerase can only add on to an existing strand
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Ribozymes
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catalytic RNA that can catalyze reactions on their nucleotides
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DNA
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restores phosphodiester linkages between adjacent fragments on the lagging strand during DNA replication
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The tertiary structure of a protein is determined by
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R group interactions
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RNA processing in Eukaryotes
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1. addition of a G cap
2. addition of a poly tail 3. removal of introns 4. splicing of exons |
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chaperone proteins
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help other proteins fold correctly
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genes code for
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1. polypeptides
2. enzymes 3. RNA |
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mRNA
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transfers information from the nucleus to the cytoplasm
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Difference in nucleotides and nucleosides
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nucleotides have a phosphate group, nucleosides do not
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terminator sequence
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signals for the termination of transcription
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Exons
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the parts of RNA that are translated
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Three processes that are required between transcription and translation
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splicing, capping, addition of the poly A tail
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Bilayer
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arrangement of phospholipids in the plasma membrane with the hydro-phobic fatty acid tails on the inside
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transmembrane
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A protein that forms an ion channel through a membrane is most likely to be
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Concentration gradient
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there is more of a substance on one side of a membrane than on the other
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osmosis
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diffusion of water across a semipermeable membrane
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How many codons specify amino acids?
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61
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When placed in hypertonic solution, animal cells
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shrink
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Purines
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Adenine and guanine
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tRNA
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the link between mRNA and a protein
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Transcription
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synthesizes all types of RNA from DNA templates
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Process of signal transduction
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1. binding of ligand to receptor
2. conformational change to receptor protein 3. alteration of cellular activity 4. conformational change in ligand |
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Chemical signal transduction pathways
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involve the binding of a signal molecule to receptor
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Types of Bonds Strongest to weakest
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1. Covalent
2. Ionic 3. hydrogen 4. van der waals |
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primary induction
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when the notochord sends a sgnal to the ectoderm to form the neural plate from the overlying epithelium
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Sonic Hedgehog (Shh)
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a protein secreted from notochord that activates neural tube cell receptors and directs motor neuron formation
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neural crest cell migration begins
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in anterior and posterior neural crest cells migrate later
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3 primary vesicles of brain formation
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forebrain, midbrain, hindbrain
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meiosis
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process that leads to the production of the megaspore
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How many functional megaspores from one mother cell?
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1
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What is the effect of gibberellin on gene activity of aleurone cells
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It activates transcription of the amylase gene
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What does Gibberellin do to the cytoplasmic Ca2+ of aleurone cells?
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decreases
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aleurone
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one of the two major cell types of the endosperm
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Gibberlins can activate transcription through this signaling intermediate
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cGMP
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Order of events for female gametophyte
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megasporocyte, megaspore, megagametophyte
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Mitosis without cell division
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occurs during meiosis and happens when new nuclei are formed within one cell
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Fertilization in higher plants involves
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The release of two sperm cells into a synergid and the subsequent fertilization of the egg and central cell.
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The acrosome reaction occurs in
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sperm
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the acrosome reaction is caused by
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g-actin polymerizing to form f-actin
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Fertilization in animals can occur during
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first prophase, second metaphase, first metaphase, or after meiosis is complete depending on the animal
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The slow, permanent block to polyspermy in sea urchins
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is the hardened and raised fertilization envelope
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In frog eggs, the site of sperm entry
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determines the future ventral side
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Removal of the micromeres in a sea urchin embryo results in
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the inability for the embryo to gastrulate
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The grey crescent
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is observable in a frog zygote
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After 6 rounds of mitosis in a fly embryo, how many cells and nuclei are there?
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1 cell, 64 nuclei
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The function of gastrulation in all animals
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to create the gut tube
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The dorsel lip of an amphibian's blastopore
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contains signaling molecules that help to organize the embryo
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During gastrulation in a chick embryo, all 3 parts of the embryo are formed from
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the epiblast
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The hypoblast
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supports the formation of the parts of the embryo from the epiblast
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Protosomes
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animals that form the mouth invagination first during gastrulation
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The cells on the vegetal pole of the frog embryo
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are larger than the cells on the animal pole
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The dorsal lip of the blastopore
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leads to the establishment of the embryonic axes
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Transcription factor
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a protein that interacts with DNA and regulates transcription of a particular
gene |
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What kind of protein is Shh?
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cell-signaling molecule
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Neurulation
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initiates the formation of the nervous system
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Neurulation is initiated by
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the notochord through primary induction
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the neural tube differentiates into
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the brain, optic vesicles, spinal cord
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neurite
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extension of a neuron that can either become an axon or dendrite
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The growth cone in neurites
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1. contains meshwork of actin and microfilaments
2. selects the direction of growth 3. guide axons to their targets 4. are important in neurogenisis ` |
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far-red light
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stops the germination of plants
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red light
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allows the germination of plants
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2 Organelles that can store Ca2+ to later be released into the cytoplasm
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E.R.
mitochondria |
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First event of opening stoma
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activation of the blue light receptor
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Last event of stomatal opening
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water into the guard cell
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First event of closing a stoma
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activation of receptor by ABA
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Last event of closing stomata
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water efflux from guard cells
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Calmodulin
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small, water soluble protein that is activated by Ca2+
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How do plants get phosphate from the soil?
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secondary active transport with H+
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where does the optic vesicle form?
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the forebrain
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Myelination
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allows axons to have smaller diameters and transmit action potentials rapidly
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motor unit
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a motor neuron and the muscle fiber it innervates
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axon hillock
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spike initiating zone
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spatial summation
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when two different inputs arrive at an axon at the same time, their effects on the membrane potential of the spike initiating zone are cumulative
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temporal summation
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the effects of the inputs decay slowly so if a second one arrives shortly after the first, its effects will be additive
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Action potentials are produced
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when/if the membrane potential of the spike initiating zone is brought to threshold
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Synaptic Integration
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the neuron can integrate thousands of inputs at any given time, they are combined and integrated to determine whether an action potential is created
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muscle contraction
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caused by myosin molecules pulling the actin filaments toward the center of the sarcomere
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myosin structure
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globular head, tail, connected by a hinge region
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Where is the myosin controlling Ca2+ stored?
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the sarcoplasmic reticulum
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a sensory stimulus always results
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in a change of the membrane potential of the receptor cell
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information about the sensory stimulus is always
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carried to the central nervous system by action potentials
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the membrane potential of a photoreceptor cell
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changes in response to changes in light
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When is a G-protein active?
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When it has a GTP bound to it
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Which proteins do 7td always interact with
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G-proteins
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Which transmitter is released by the photoreceptor
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glutamate
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ON bipolar cells
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hyperpolarize in response to glutamate and depolarize in response to light
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OFF bipolar cells
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depolarize in response to glutamate and hyperpolarize in response to light
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The receptive fields of ganglion cells are arranged in
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concentric circles
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how do receptors in the alveoli maintain the partial pressure of CO2?
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by adjusting the rate of breathing
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surfactant
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a lipoprotein that reduces surface tension
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the concentration of gas dissolved in water
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is proportional to the partial pressure of the gas
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