FINAL EXAM

Question 1

Light can be used as a source of ______ and _________.

Answer 1

A source of energy and information.
Energy that directly or indirectly supports sustains all organism. Information is used to gain knowledge about the physical world that surrounds the organism.

Question 2

Can organisms use light both as energy and information?

Answer 2

Yes, organisms have evolved to exploit both.

Question 3

Light is a ______ of discrete particles called ________. What is the called?

Answer 3

WAVE of discrete particles called PHOTONS.

The particle-wave duality.

Question 4

What do the wave-like properties of light determine?

Answer 4

The wave-like properties reflect the type of energy making up the light. Using the wavelength, we perceive this energy in different colors based on their strength.

Question 5

How does light interact with our world?

Answer 5

Light interacts with matter like a particle. For light, the photons interact with matter and have 3 possible fates:

1) REFLECTED OFF OBJECT
2) TRANSMITTED THROUGH OBJECT (passes through object)
3) ABSORBED BY OBJECT

Question 6

Define the particle-wave duality?

Answer 6

The particle-wave duality states that light can act as both particles (photons) or waves.

Question 7

What are Cataracts?

Answer 7

It is a vision deteriorating disease which changes the lens of the eye, making it more opaque. Our lenses are made of proteins, water, and absorb certain wavelengths of light. Due to Cataracts the protein in the lens gets denatured, which decreases the transmittance (spreading) of clue light.

Question 8

What does denature mean?

Answer 8

It is the process modifying the molecular structure of a protein.

Question 9

How far away is the Earth from the Sun?

Answer 9

150 million kilometers, this distance keeps the water in liquid state.

Question 10

When a photon hits an object, what happens?

Answer 10

When a photon hits an object is can be absorbed, reflected, or transmitted. If it is absorbed, the photon is transferred into an electron and used for energy.

Question 11

When are photons allowed to be absorbed?

Answer 11

A photon can only be absorbed if the accepting electron has the same energy as the photon. The energy of the electron is defined as the distance between the electron’s ground state and excited state. If the energy is not equal the photon is transmitted or reflected.

Question 12

What is a pigment?

Answer 12

When the photon is absorbed, we call the matter that it interacts with a pigment. Pigments are able to absorb only certain types of color, and the color represents the amount of energy in the wavelengths of light. In this figure, you can see the relationship of energy, wavelength and color.

Question 13

How do we see colors?

Answer 13

We see the color that is not absorbed. For example, plants absorb wavelengths of red and blue light. However, they do not absorb green light, which is then reflected or transmitted into our eyes.

Question 14

How does a pigment absorb light?

Answer 14

Chemically speaking, they often have alternating double and single bonds. These are called conjugated double bonds.It results in delocalization of electrons. Therefore, they are not closely associated with any atoms and thus are more available to interact with a photon of light. When a photon interacts with these, their chemical nature can be altered. The photon is essentially absorbed, and no longer exists.

Question 15

What is the central dogma?

Answer 15

The central dogma of molecular biology describes the two-step process, transcription and translation, by which the information in genes flows into proteins: DNA → RNA → protein. Transcription is the synthesis of an RNA copy of a segment of DNA. RNA is synthesized by the enzyme RNA polymerase.

Question 16

A molecule with _______ bonds are insoluble in water.

Answer 16

Non-Polar

Question 17

What is a hydrophilic molecule?

Answer 17

A hydrophilic molecule or portion of a molecule is one whose interactions with water and other polar substances are more thermodynamic ally favorable than their interactions with oil or other hydrophobic solvents.

Question 18

What are the major characteristics of life?

Answer 18

Major Characteristics of Life 
o Basic Building Blocks 
 Carbohydrates 
 Lipids 
 Proteins
 Nucleic Acids 

o Information System
 DNA and genetic information.
 Information flows through central dogma.

o Energy Use and Metabolism
 All cells need a source of carbon and a source of energy.
 All cells use energy and carbon to build macromolecules and carry out the processes of life.
 All cells use ATP as the main energy carrier

Question 19

Absorption Spectrum

Answer 19

A spectrum of EM radiation transmitted through a substance that tells you how much of each type of radiation is absorbed by the substance

Question 20

Photoreceptor

Answer 20

Specialized cells on the back of the retina that absorb light and process it into neural impulses for interpretation in the brain.

Question 21

Two Major Functions of Light in Living Systems

Answer 21

o Vision
 In animals, light is used primarily for vision. Light allows us to see the world around us which can help us identify different aspects of our surrounding environment such as food or shelter or predators.
o Energy
 Plants and some bacteria have the ability to carry out photosynthesis. They use light energy to drive a reaction that makes glucose. They use light as an energy source to make food.

Question 22

What are opsins?

Answer 22

o Opsins are a group of proteins found in the eye that are made sensitive to light via the pigment retinal. When an opsin protein binds to retinal, it forms a protein complex called rhodopsin. o Different opsins bind to different conformations of retinal which allows us to see a variety of different colours. o Retinal consists of a conjugated system that allows delocalized electrons to bounce around. When retinal absorbs light, the delocalized electrons get “excited” momentarily. This causes a conformational change in the retinal which starts a chain reaction that actives the rhodopsin complex and turns the light energy into neural impulses.

Question 23

Cell Theory

Answer 23

 All organisms are made of cells. (Unity) (Pattern)
 Cells are the basic unit of life. (Unity)
 All cells come from other cells. (Unity) (Mechanism)

Question 24

Evolution

Answer 24

All organisms come from other organisms and all organisms have descended from a common ancestor. (Unity)  Characteristics of a population change over time. (Diversity) (Pattern)  Evolution requires genetic variation. (Diversity)  Individuals with certain heritable traits produce more offspring and these traits get passed on more which causes evolution. (Mechanism)

Question 25

Three Domains of Life

Answer 25

o Prokaryotes  Small, single-celled organisms that lack a nucleus and many other membranebound organelles. o Archaea  Small, single-celled organisms that lack a nucleus and many other membranebound organelles. Live in extreme environments. Share similarities with both eukaryotes and prokaryotes but are still structurally distinct from both domains. o Eukaryotes  Larger than prokaryotes, membrane-bound nucleus and organelles.