Biology 1202B Lecture 11: Lecture 11 .docx

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blushsea-lion259

24 Apr 2013

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1952 hershey & chase: studied e. coli, the genetic material of the phage (viruses that infect bacteria) was dna not protein. The isotope used to label proteins was found in phage coats after infection but was not found in the infected cell or in progeny phages. Therefore, protein is not the genetic material: established the term transformation the conversion of a cell"s hereditary type by the uptake of dna released by the breakdown of another cell. 1953 watson, crick & franklin: used an x-ray diffraction model to study the structure of dna. The dna molecules within the fibre were cylindrical (about 2nm in diameter) Major patterns of atoms repeated at intervals of 0. 34 nm and 3. 4 nm within the. Distance between each pair of bases = 0. 34 nm. Each full twist of the dna double helix = 3. 4 nm: dna structure is a double helix.

Related Questions

Material Science

Question 1

Muscle fibers slide smoothly across each other in both directions.

True

False

Question 2

Cell membranes are composed of single layers of fat molecules.

True

False

Question 3

In mammals, the percentage composition of fats and minerals is roughly the same.

True

False

Question 4

Both RNA and DNA have a double helix structure.

True

False

Question 5

The primary constituents of muscles are

	a)	the proteins kerotin and actin
	b)	the proteins lycine and actin
	c)	the proteins actin and liposine
	d)	the proteins glycine and lycine
	e)	the proteins myocin and actin

Question 6

Hydroxyapatite is a component of endoskeletons.

True

False

Question 7

There are thousands of types of amino acids.

True

False

Question 8

Amorphous silicon is a component of some biomaterials.

True

False

Question 9

The biosynthesis of both collagen and polysaccharides starts in the cell nucleus.

True

False

Question 10

After going through alkyline hydrolysis, the remaining solids are primarily hydroxyapatite.

True

False

Question 11

Calcium carbonate is a mineral found in some biomaterials.

True

False

Question 12

Proteins, chitin, and cellulose are build up from proteins

True

False

Question 13

There are thousands of types of proteins.

True

False

Question 14

Chitin is the most abundant natural polymer.

True

False

Question 15

Keratin is formed from a structure of living cells.

True

False

Question 16

Some biopolymers are hard.

True

False

Question 17

Polymeric biomaterials are comprised of collagen and elastin.

True

False

Question 18

Cell membranes are made of double layers of proteins.

True

False

Question 19

Which is NOT an example of a hard biopolymer?

		a)Eggs
		b)Insect Shells
		c)Hooves
		d)Nails
		e)Cellulose

Question 20

Polysaccharides are built up hierarchically from amino acids.

True

False

Question 21

Unit cells have faces that are

	a)	rhombus
	b)	square
	c)	rectangular
	d)	parallelegrams
	e)	circular

Question 22

Unit cells are

		a)the building blocks of crystalline material
		b)the building blocks of DNA
		c)the building blocks of polymers
		d)the building blocks of amorphous materials
		e)the building blocks of biomaterials

Question 23

Which radioactive semi-metal is the only element with a Simple-Cubic (SC) structure?

		a)Polonium
		b)Uranium
		c)Radium
		d)Plutonium
		e)Dilthium

Question 24

The common crystal structures in metal are

		a)FCC, BCC, HCP
		b)FCC, BCC, HCP, and SC
		c)HCC, BCC, FCP
		d)HCC, BCC, FCP and SC
		e)FCC, SEC, BCC

Question 25

Diffraction results in

		a)constructive interference
		b)delamination of the planes
		c)reverse polarization
		d)altered planar spacing
		e)destructive interference

Question 26

Unit cell indexing schemes provide

		a)location information for grain boundaries
		b)descriptions of the atoms, planes, and axis directions
		c)diffraction indexes for the crystal material
		d)the location of the unit cell in the larger crystalline matrix
		e)the packing arrangement

Question 27

Hexagonal crystal structures cannot be close-packed.

True

False

Question 28

To determine crystal structure and spacing, scientists use

		a)magnetic resonance imaging
		b)X-ray diffraction
		c)optical microscopes
		d)scanning electron microscopes
		e)atomic force microscopes

Question 29

A scanning probe (aka atomic force) microscope can be used to image and manipulate individual atoms.

True

False

Question 30

Crystal planar density is taken as

		a)the number of atoms per unit area for a plane
		b)the planar stacking order
		c)the number of atoms that are closely packed
		d)the number of equivalent atoms per unit cell
		e)the number of atoms per unit length for an axis

Question 31

The atomic packing factor represents

		a)the mass ratio of the unit cell
		b)the number of nearest-neighbor atoms
		c)the fraction of solid sphere volume in the unit cell
		d)the unit cell edge length (a) divided by the atomic radius (R)
		e)the density of the material

Question 32

When an elemental solid can have more than one crystal structure, it is said to have

		a)allotropy
		b)polymorphism
		c)polytropy
		d)elemorphism
		e)anthropomorphis

Question 33

The crystallographic linear density

		a)is determined by the atomic packing factor
		b)is six for HCP unit cells
		c)is five for BCP unit cells
		d)is determined by the coordination number
		e)is how many atoms lie along a unit length in that direction

Question 34

Bragg's law specifies

		a)the condition for when electrons will be refracted upon striking a crystal
		b)the condition for when light will be polarized upon striking a crystal
		c)the condition for when x-rays will be absorbed upon striking a crystal
		d)the condition for when x-rays will be refracted upon striking a crystal
		e)the condition for when light will be refracted upon striking a crystal

Question 35

Two features of a crystal unit cell structure are

		a)atomic number and elemental packing factor
		b)the number of interstitial and host atoms
		c)coordination number and atomic packing factor
		d)the number of faces and the number of atoms
		e)the number of substitutional and interstitial atoms

Question 36

Imperfections in semiconductors are used to create transistors and other electronic devices.

True

False

Question 37

The majority of crystalline solids are single crystals

True

False

Question 38

The grain structure of a polycrystalline material can be observed in the material without significant preparation.

True

False

Question 39

There are three types of electron microscopes, Transmission (TEM), Scanning (SEM), and Tunneling (TUEM).

True

False

Question 40

Defects are important for solid catalysts

True

False

Question 41

The mean intercept length is a measure of grain diameter.

True

False

Question 42

Imperfections in materials do not generally change their properties.

True

False

Question 43

The mean intercept length is computed from the average length of a grain boundary edge.

True

False

Question 44

Catalysts chemically combine with the reactant molecules in order to speed up the reaction.

True

False

Question 45

For a particular material, the higher the temperature the greater the number of vacancies.

True

False

Question 46

A twin boundary is a linear defect where the screw angles on each side of the boundary are equal.

True

False

Question 47

The regular pattern of crystal order is disrupted at a grain boundary.

True

False

Question 48

Solid solutions can only be formed by liquid material cooling to a solid.

True

False

Question 49

Alloys do not usually have significantly difference properties of the constituent metals.

True

False

Question 50

When an atom is missing from a crystal structure position, it is referred to as a self-interstitial.

True

False

byzantiumpig518

Question 1

Which of the following provides the best description of adifference between prokaryotic and eukaryotic cells?.l.14.3>

The cell membrane of prokaryotic cells contains proteins, whilethe cell membrane of eukaryotic cells contains only lipids andcarbohydrates.

The DNA in eukaryotic cells is enclosed in the nucleus, whilethe DNA in prokaryotic cells is not separated from the rest of thecellÃ¢â¬â¢s contents.

Eukaryotic cells have cell walls that consist mainly of sugars,while prokaryotic cells do not.

Prokaryotic cells contain chloroplasts and mitochondria, whileeukaryotic cells do not contain specialized organelles.

Question 2

Cellular respiration is a process involving the breakdown ofglucose molecules in order to generate energy for cellularactivities. Given the general reaction below, which of thefollowing best describes the products labeled x andy?

C₆H₁₂O₆ + O₂ Ã¢â â _x___+ __y___ + energy.l.18.8>

The products are CO (carbon monoxide) andH₂O₂ (hydrogen peroxide), which thendecompose into carbon dioxide (CO₂) and water(H₂O).

The products are H2O (water) and CO₂ (carbondioxide), which then undergo anaerobic respiration.

The products are CO₂ (carbon dioxide) andH₂O (water), which then become the reactants forphotosynthesis.

The products are O₂ (oxygen) and H₂O(water), which are then used for growth and to keep the organismhydrated.

Question 3

If a researcher added a quantity of phospholipid molecules to abeaker of water, what would be most likely to happen to theorientation of the phospholipid molecules?.l.14.2>

They would break apart, and the remaining lipid tails wouldfloat up and form a layer on the surface of the water.

Their lipid tails would align within a spherical double layerwith their phosphate heads in the water inside and outside thesphere.

They would form a single-layered sphere with the phosphate headspointing outward and the lipid tails pointing inward.

Their lipid tails would adhere to the glass of the beaker andtheir phosphate heads would float in the water.

Question 4

While looking at a cell under a microscope, a scientist is ableto see a biological molecule. This molecule is a nucleic acid witha ladder structure and contains the nitrogenous bases adenine,thymine, cytosine, and guanine. Based on this information, whatconclusion can the scientist draw regarding this nucleicacid?.l.18.1>

The nucleic acid is RNA and would be found in the cellÃ¢â¬â¢snucleus.

The nucleic acid is RNA and would be found in the cytoplasm.

The nucleic acid is DNA and would be found in the cytoplasm.

The nucleic acid is DNA and would be found in the cellÃ¢â¬â¢snucleus.

Question 5

Which of the following is needed for cellular respiration tooccur?.l.18.8>

Sodium

Oxygen

Water

Nitrogen

Question 6

What would be the most likely effect if the side chain of an aminoacid group was unable to vary its structure?.l.18.4>

The organism would not be able to make and store starches.

The organism would not be able to process glucose moleculeseffectively.

The organism would not be able to regulate the creation ofspecialized cells.

The organism would not be able to make more than one type ofprotein.

Question 7

During photosynthesis, unused oxygen atoms form oxygen gas(O₂) which is released as a waste product. How did theseoxygen atoms originally enter the plant?.l.18.7>

They were part of the ATP molecules gathered by thechloroplasts.

They were part of the sugar molecules(C₆H₁₂O₆) the plant brought in forfood.

They were part of the carbon dioxide (CO₂) moleculesthat entered through the leaves.

They were part of the water molecules (H₂O) pulled inthrough the roots.

Question 8

Which of the following organelles houses DNA in eukaryoticcells?.l.14.3>

Endoplasmic reticulum

Golgi apparatus

Nucleus

Mitochondrium

Question 9

M. J. Schleiden shifted the scientific community's attention tocellular processes with his.l.14.1>

attention to disproving spontaneous generation

publication of ideas on cell generation

theories on the division of cells

claim that cells were the basic unit of all plant matter

Question 10

While the average human is able to hold his or her breath forapproximately one minute, a whale can dive for over 30 minuteswithout returning to the surface. Which of the following correctlydescribes this difference?.l.18.10>

Whales need less energy than humans.

Whales gather energy from their environment better thanhumans.

Whales are able to tolerate the products of cellular respirationbetter than humans.

Whales have a slower cellular respiration metabolism rate thanhumans.

Question 11

What can you conclude about the advantage of the cell membranehaving hydrophobic ends in the phospholipid bilayer?.l.18.3>

The cell requires the ability to digest and eliminateenzymes.

The cell requires a barrier between itself and itsenvironment.

The cell requires a means to store starches and glucose.

The cell requires a structure for eliminating waste.

Question 12

What would be the most likely outcome if the ribosomes of a cellwere damaged and stopped functioning?.l.14.3>

The cell would lose structure and shape.

Cell growth and repair would slow or stop.

Cell waste would no longer be processed.

The cell would produce more mitochondria.

ivoryjackal958

Biology 1202B Lecture 11: Lecture 11 .docx

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