Bio Exam 2

Hershey and Chase used _____ to radioactively label the T2 phage's proteins. 35S 222Ra 32P 92U 14C

35S

respiratory surface for gas exchange, diaphragm and lungs mix the air that helps promote gas exchange, lots of branching leads to increased gas exchange

lungs

Which statement is true of water? (a) The O atom in water has a partial positive charge. (b) The H atoms in water have partial positive charges. (c) Its polarity results from hydrogen's high electronegativity. (d) About 50% of the average cell's mass consists of water. All of the above except for (a).

(b) The H atoms in water have partial positive charges.

Which statement is part of the explanation for water's high cohesion? (a) Oxygen has four valence orbitals. (b) Oxygen is much more electronegative than hydrogen. (c) Water can hydrogen-bond with other kinds of molecules. All of the above. Both (a) and (b).

Both (a) and (b).

- AT and CG occur in the same frequency - % of each nucleotide type in DNA was about the same - This info lead us to conclude that DNA was in a double helix and there were slight differences between organisms

Chargaff's findings

The radioactive isotope 32P labels the T2 phage's _____. protein coat head DNA tail base plate

DNA (The T2 phage consists of a protein coat and DNA. It is the DNA that contains P.)

o Optimal condition: temp and pH o Other molecules • Co-factors (non-protein, metals) • Co-enzymes (organic=other proteins like vitamins) • Inhibitors (competitive vs. non-competitive) • Allosteric regulator of multisubunit enzymes

Factors affecting enzymes (rate and on/off)

- X-ray diffraction → structure of DNA is a helix- two strands (and strands were a certain distance wide) but she had not published it yet

Franklin and Wilkins

Who demonstrated that DNA is the genetic material of the T2 phage?

Hershey and Chase

- Active site lowers activation energy and speeds up reaction - Serves as a platform to bind on to promote chemistry - Substrate bonds are stressed to destabilize it - Microenvironment for chemistry to occur (ex: change in pH) - Forms a temporary covalent bond with the substrate

How does an enzyme lower Ea?

Which answer helps to explain how many hydrogen bonds a water molecule can form? Oxygen's valence shell has four orbitals. Water can ionize, making hydronium and hydroxide ions. The oxygen atom has six protons. The angle between H-O bonds in water is 180∘. Oxygen makes two covalent bonds.

Oxygen's valence shell has four orbitals.

- Double helix - Discovered the angle of nucleotides in DNA - Base pair rule (purine + pyrimidine) - Antiparallel - Phosphate backbone - Bases held together by hydrogen bonds - Covalent bonds held together the single polymer chain (phosphodiester bond) - Nucleic acids of DNA o Pyrimidine: one organic ring (T and C) o Purine: two organic rings (A and G)

Watson and Crick

- Temperature: increases kinetic energy of molecule, breaks up non-covalent interactions - pH: lower pH, increase H+ ions around the cell, affects hydrogen bonding and ionic bonding - Salts (ion concentrations): ionic bonds - Binding to other proteins or molecules such as a substrate - environment

What factors can influence protein shape?

- Enzymes: selective acceleration of chemical reactions (tyrosinase) - Structural: support (collagen) - Storage: storage of amino acids - Transport: transport substances around the body (hemoglobin) - Hormonal: coordination of an organism's activities - Receptor: response of cell to chemical stimuli - Contractile and motor: movement (motor proteins) - Defensive: protection against disease

What functions do proteins serve?

moves solute against gradient, requires energy

active transport

___________ makes water stick to hydrophilic surfaces, such as cell walls, results from hydrogen bonds between water and other polar molecules

adhesion

large surface area, thin, may be only 1 or 2 cells thick, surrounded by capillaries, little distance to have to diffuse, great adaptations for diffusion

alveoli

animals near water source, requires little energy to convert waste, very toxic

ammonia

carry O2 blood from heart to rest of the body, big tubes, made of smooth endothelium inside (coats a lot of interior of body), helps resist friction, promotes bulk flow, gets blood that comes right from the heart, have thick wall of muscle to counteract this pressure from the heart pumping the blood forcefully

arteries

Blood goes from heart to arteries through capillaries and then through veins and back to the heart

blood flow

o Increase in free H+ cause Hb to change shape and release O2 (increase in free H+= decrease pH) o Can figure out whether Hb is binding O2 better or worse at certain pH o Drop in pH lets Hb let go of O2 better

bohr effect

thin layer of cells, increasing surface area, promotes diffusion, slowed the flow to allow time for gas exchange, decreased the pressure, increased time for gas exchange, allows for maximum diffusion between blood and interstitial fluid

capillaries

__________ tends to keep water molecules that are away from surfaces from separating. result from hydrogen bonds between water molecules

cohesion

Antidiuretic hormone (ADH) makes the _____ permeable to water. ascending portion of the loop of Henle collecting duct Bowman's capsule proximal tubule descending portion of the loop of Henle

collecting duct

oxygen binds to 1 subunit, leads to increased affinity for oxygen in the other subunits, shape (conformational) change in hemoglobin, helps it bind oxygen more quickly, increase affinity of O2 pick-up (lungs) and delivery (tissues)

cooperative binding

(negative pressure pulling air in): muscular structure, expands volume of lungs as it contracts, leads to reduced pressure inside the lungs, lung pressure less then air pressure, so it moves into the lungs, controls how much air is coming into the lungs

diaphragm

NET Movement of molecule (solute) from high concentration to low concentration until we reach equilibrium, refers to any molecule/solute, involves moving down gradient

diffusion

Birds, insects, and many reptiles excrete nitrogenous waste in the form of uric acid, which _____. a. is much more soluble in water than other nitrogenous wastes, but is energetically costlier than other nitrogenous wastes to synthesize b. reduces water loss compared to other nitrogenous wastes, but is highly toxic c. is not very toxic compared to other nitrogenous wastes, but requires the loss of a lot of water with its excretion d. reduces energy use compared to other nitrogenous wastes, but is highly toxic to animals that produce it e. reduces water loss compared to other nitrogenous wastes, but requires more metabolic energy to produce

e. reduces water loss compared to other nitrogenous wastes, but requires more metabolic energy to produce (Because uric acid is not very soluble in water, it can be excreted in a paste-like form with very little loss of water. However, its synthesis requires the hydrolysis of ATP.)

- Filtration - Selective reabsorption: body pulls back things it needs - Secretion: helping body get rid of toxins and non necessary solutes found in the blood - Excretion: leaves the body

excretory systems

Each water molecule is joined to _____ other water molecules by ____ bonds. four ... hydrogen two ... hydrogen two ... polar covalent four ... polar covalent three ... ionic

four ... hydrogen

the uptake of molecular oxygen (O2) from the environment and the discharge of carbon dioxide (CO2) to the environment

gas exchange

(4 chambered): provides pressure, is a muscle, provides force to push blood around body (bulk flow), 4 chambered so we don't mix the two blood populations flowing through our body (oxygenated and deoxygenated, O2 rich and CO2 rich blood)

heart

protein, respiratory pigment, has 4 subunits each made from single polypeptide chains that fold into particular structure, 1 iron (binds O2) and 1 heme molecule found within each subunit, can transport 4 O2 molecules per hemoglobin protein

hemoglobin

- The maintenance of an internal environment within rather narrow limits; the state of steady internal physiological condition - Maintaining a "steady state" that allows organisms to survive in varying (sometimes stressful) environments - In multicellular organisms, homeostasis is achieved by constantly regulating the composition of the fluid surrounding the cells of all tissues

homeostasis

The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases. ionic bonds hydrophilic interactions hydrogen bonds covalent bonds S—S bonds

hydrogen bonds

Despite its cohesion, water can flow because ... hydrogen ions can move between molecules. hydrogen bonds are too weak to affect movements. hydrogen bonds break and re-form rapidly. many water molecules have no hydrogen bonds. None of the above.

hydrogen bonds break and re-form rapidly.

higher solute concentration relative to ________ (cell) o Higher solute concentration on outside relative to the cell, water will move out of the cell, cells will shrivel o Plant cells become plasmolyzed in this state, shrivel and wilt

hypertonic

lower solute concentration relative to _______ (cell) Plant cells in this state, water will move in and cell expands, but cell wall keeps cell in tact even with the water pressure (Turgid) plants perk up, they like to be in hypotonic environments

hypotonic

same solute concentration relative to ________ (cell) o Our cells prefer this state o Plant cells become flaccid at this state and start to wilt

isotonic

After allowing phages grown with bacteria in a medium that contained 32P and 35S, Hershey and Chase used a centrifuge to separate the phage ghosts from the infected cell. They then examined the infected cells and found that they contained _____, which demonstrated that _____ is the phage's genetic material.

labeled DNA ... DNA

Under the influence of antidiuretic hormone (ADH), _____ is produced. urine containing more glucose bloody urine urine containing a lower concentration of urea more concentrated urine less concentrated urine

more concentrated urine

the biological process of controlling solute concentration and water balance (osmosis in or out) generally by controlling movement of solutes o Maintain homeostasis o Control solute concentration and balance H2O gain and loss o Maintains volume of cell (volume regulation)

osmoregulation

- NET Movement of water through a semipermeable membrane - Moving according to its concentration gradient (moves high free water concentration to low free water concentration) low solute concentration to high solute concentration - refers to water, involves diffusion of water across membranes

osmosis

measures the O2 saturation of hemoglobin at different pressures [O2], sigmoidal

oxygen dissociation curve

The water molecule has a bent shape because ... covalent bonds are never straight. hydrogen atoms have a partial negative charge. hydrogen atoms attract one another. oxygen has two unbonded pairs of valence electrons. None of the above; water molecules are linear.

oxygen has two unbonded pairs of valence electrons.

A nucleotide is composed of a(n) _____. phosphate group, a nitrogen-containing base, and a five-carbon sugar phosphate group, a nitrogen-containing base, and a hydrocarbon amino group, a nitrogen-containing base, and a five-carbon sugar sulfhydryl group, a nitrogen-containing base, and a five-carbon sugar glycerol, a nitrogen-containing base, and a five-carbon sugar

phosphate group, a nitrogen-containing base, and a five-carbon sugar

The unequal sharing of electrons within a water molecule makes the water molecule _____.

polar

what type of bond is found between the oxygen and hydrogens?

polar covalent

order of amino acids, form peptide bonds (covalent bonds) very strong, linking amino acids together into a chain

primary structure

- Made of amino acids - Form polypeptide chains - Fold into a particular shape that is required for a specific function - Assemble (if made of more than one polypeptide) - Folding is influenced by change in environmental conditions (can be denatured/unfolded and renatured/refolded)

protiens

same types of chemical bonds as tertiary structure, also between R groups, 3 or 4 polypeptides (subunits) that has folded into its shape and has come together to form quaternary structure

quaternary structure

travel through blood vessels and can squeeze through capillaries, purpose: transports oxygen and also CO2, biconcave (more surface area for exchange), no nucleus to make space for hemoglobin instead, small, 10 micrometers across, made of thin layer of cells, single membrane surrounding the cell good for diffusion, 300 million hemoglobin proteins in each red blood cell

red blood cells

hydrogen bonds between the backbone

secondary structure

Why do organisms need gas exchange mechanisms to provide oxygen to cells?

so we can make ATP so our cells can do things

_________ most commonly occurs at air-water interfaces, where it resists breakage of the surface. Hydrogen bonds tend to pull water molecules at the surface together, reducing the curvature of the surface. result from hydrogen bonds between water molecules

surface tension

interaction between the R groups, connection between beta sheets and alpha helix through R groups, ribbon model, can form ionic bonds and also hydrogen bonds, form hydrophobic interactions, NON COVALENT bonds except for 1= disulfide bonds

tertiary structure

capacity of a solution to cause water to move into or out of a cell

tonicity

(loss of water from the leaves)-cohesion tension mechanism • Depends on dif in water potential between leaves and roots, less potential, and on the properties of water (cohesion=water pulls water, adhesion=water sticks to xylem) • Pulling water up the tree • Requires no energy from the plant

transpiration

o Hydrophilic= water loving, they are polar, electronegative and make portion of molecule polar, have polar and electrically charged side chains o Hydrophobic= non polar, don't readily dissolve in water, water fearing, have nonpolar side chains

types of amino acids

still requires some water to be able to get rid of the urea, humans

urea

takes a lot of energy to generate this type of waste, limited access to water, organisms that live in dry climates, does not dissolve in water, helpful for water retention in the organism, energetically inefficient, lightweight, less toxic

uric acid

have valves (encourage the blood to go back to the heart, prevents back flow), not as much pressure so not as much muscle surrounding veins like the arteries

veins

potential energy stored in water due to its special distribution, depends on where the free water is o More free water, higher water potential o Fewer free water, lower water potential

water potential

specialized tissue, water travels through them so water molecules can flow very fast, specialized cells in plants make up vascular system

xylem