BIO 101-M1

Question 1

What is science?

Answer 1

The word “scienta” means knowledge. Science means to know or knowledge and is

1. a pursuit of truth through objective analysis
2. determines principles from observations of any occurrence
3. process of inquiry is repeatable and testable
4. seeks natural causes from natural phenomenon

Question 2

What is the scientific process/method?

Answer 2

The scientific method is a way of learning about the natural world by applying certain rules of logic to the way information is gathered and conclusions are drawn.

Question 3

Outline the scientific process:

Answer 3

1. Observe- make careful observations and ask questions about the observations. Questions should be reasonable consistent with existing knowledge.
2. Quantify- describe
3. Hypothesis-develop a testable hypothesis (possible explanation) as a possible answer to your question (should be a statement not a question). It should be possible to prove it false, but can never be proved true. Can only support or refute a hypothesis.
4. Prediction-make a prediction based on hypothesis, and test it with a controlled experiment. Prediction should regard what should occur if hypothesis is correct.
5. Test- actual experiment. Run a controlled experiment- randomly assigned and divided into a control group and an experimental group, treated in same way except for independent variable. If test results do not support explanation ad alternative should be generated and tested.
6. Conclusion-draw a conclusion based on results of experiment. Interpret the data. Look at statistical significance of the data to see if it is due to chance or not. Repeat the experiment and see if it yields similar results

Question 4

Design an Experiment?

Answer 4

-Controlled (so one explanation for results)

Ex: drug being tested for depression. Use a double blind, or blind test to randomly assign people to 2 different groups, the experimental group is given the drug for depression, the control group is given a placebo. Compare condition after and make sure cofounding variables are ruled out and taken into consideration.
 Randomly assign to 2 groups
 Group 1 (control group):
 Group 2(experimental group):
 Both groups treated in same way except for the independent variable whose effect the experiment is designed to reveal- rule out cofounding variables
 blind test, or double blind test so that researcher and participants are unaware of what is going taking place.

Question 5

What is the Miller Urey Experiment: what does it show, and why is it relevant?

Answer 5

What:

1. He took molecules that represent major components of early earths atmosphere and put them into a closed system
2. 4 gases were put into a spark chamber: methane (CH4), ammonia (NH3), hydrogen (H2) and water (H20)
3. Ran an electrical current through spark chamber to simulate lightening
4. Used a heat source to boil water and simulate the sea and a trap to collect newly formed molecules

Shows: conditions on early earth could abiotically synthesize some amino acids (make up proteins) and nucleotides (DNA and RNA)

Relevance: This is relevant because it demonstrates that cellular life could be made under conditions of early earth

Question 6

What were conditions like on early earth? How is this relevant to the origin of life?

Answer 6

	Days less than 10 hrs
	Moon closer
	Tides 100s meters high
	Volcanoes spewing sulfurous compounds
	Cyanide, carbon monoxide, methane
	Lightning storms
	Ultraviolet radiation
	No oxygen, plenty C02
This is relevant because the earth is 4.5 billion years old, but because of the extreme and crazy conditions, life was not able to originate until somewhere between 3.5 and 3.8 billion years ago.

Question 7

List the Seven Characteristics of life.

Answer 7

1. Living things contain nucleic acids, proteins, carbohydrates, and lipids
2. Living things are composed of cells
3. Living things grow and reproduce
4. Living things use energy and raw materials
5. Living things respond to their environment
6. Living things maintain homeostasis
7. Populations of living things evolve and have adaptive traits

Question 8

What are biological macromolecules?

Answer 8

They are exceptionally large molecules made up of smaller organic molecules. Macromolecules are organic which means they have at least 1 C-H bond. Carbon atoms have 4 binding sites and can link together and can bond H,0,N,P,S, etc to form an infinite variety of molecules. Four classes of biological macromolecules are:

Question 9

What are 3 types of carbohydrates and what do they consist of?

Answer 9

Monosaccharaides:
• simple sugars
• smallest molecular units of carbohydrates
Oligosaccharides:
• chains of a few monosaccharaides joined together through dehydration synthesis
• Disaccharide is one type: 2 monosaccharaides bond together
Polysaccharides:
• monosaccharaides (usually glucose) join together in long chains
• Ex: cellulose

Question 10

What are carbohydrates?

Answer 10

polymers(# of similar units bonded, formed by dehydration synthesis) of monosaccharaides (simple sugar with one unit).o CxH2xOx (carbon, hydrogen and oxygen)
o Linear or cyclic
o Polymers of glucose: starch (storage) and cellulose (structural plant cell walls)→ little difference in bonds linking glucose monomers

Question 11

What are nucleic acids?

Answer 11

• polymers of nucleotideso include RNA (ribonucleic acid-messenger molecule) and DNA (deoxyribonucleic acid-blueprint to build cell) which are

Question 12

What do nucleotides consist of?

Answer 12

both polymers of nucleotides contain:

1. a phosphate group
2. a sugar group (5 carbon ribose or deoxyribose)
3. a nitrogenous base (A,T,C,G,U)

Question 13

What are proteins?

Answer 13

Polymers of amino acid

• amino acid monomers- 20 different kinds
• difference due to R groups
• polypeptides 500-2000 amino acids long
• nearly infinite variety of polypeptides possible
• proteins do the work in cell

Question 14

Why is shape of protein important?

Answer 14

Shape is important because it is crucial in determining how a protein functions & dysfunctional misfolded proteins (prions) can transform functional proteins.

Question 15

List the 4 protein structures.

Answer 15

• 1st structure: the amino acid sequence, determined by DNA
• 2nd structure: initial folding, spirals and sheets
• 3rd structure: final 3 dimensional folding
• 4 structure: multiple polypeptides interact

Question 16

What are lipids?

Answer 16

lipids are organic compounds that are fatty acids or their derivatives and are hydrophobic (water fearing). They are used to store energy and are mostly hydrocarbon & are also used for lubricants and signaling. –lipids are no polymers.

Question 17

What is a phosphilipid?

Answer 17

A phospholipid is a lipid containing a Glycerol bonded to 2 fatty acids and negatively charged phosphate group. The region made up of fatty acid is nonpolar (hydrophobic water fearing tails). The phosphate region makes up hydrophilic heads (water loving)
 Responsible for structure of plasma cell membrane
 Arranged in double layer-bilayer, hydrophilic heads facing away from each other, hydrophobic tails point toward each other and hold membrane together

Question 18

What are triglycerides?

Answer 18

a triglyceride is 3 fatty acids bonded to one glycerol through dehydration synthesis
• used for energy storage and insulation
• fatty acids can be saturated (makes fat solid) or unsaturated (makes fats liquids, oils)

[Glycerol+3 fatty acids (chains carbon bonded to hydrogen and have acidic group COOH at one end]

• Saturated (single bond linking carbon atoms- pack closely-saturated with hydrogen )

unsaturated (double bond linking carbon atoms-not saturated with hydrogen-kinks-prevent packing so liquid or oil)

• Hydrogen can further shelf life. Hydrogenated fats are called trans fats

Question 19

What are steroids?

Answer 19

Cholesterol is one
• Found in membrane of the cell
• Not as many as phospholipids
• Useful but too much is bad since it clogs
blood stream
 component of plasma membrane
 foundation from which steroid hormones: estrogen and testosterone are made
 comes from diet and liver
 high level in blood is a risk for heart disease
Sex hormones:
•Based on cholesterol- testosterone (produced by gonads), estrogen and progesterone (determine secondary sexual characteristics regulating menstrual cycle and pregnancy.

Question 20

What are the basic features of an amino acid?

Answer 20

Consist of a central carbon atom bound to a hydrogen atom (H),
an amino group NH2
an acidic carboxyl group (COOH)
and a side chain often designated by the letter R
• Amino acids differ in their side chains

Question 21

Explain the Watson and Crick model of DNA. Outline the directionality of strands, type of helix, base pair structures, base composition and function of DNA.

Answer 21

DNA RNA
Strands: 2 1 strand nucleotides 2
Type of
helix: double helix

Base
pair: C-G, A-T C-G, A-U

Structure
Base composition: A=T, C=G A=U,C=G
Composition

Function storage info transfer info

Question 22

Explain how lipids are classified, name at least 2 lipids and their representative functions.

Answer 22

Lipids are fats that do not dissolve in water since they are non polar (have no electrical charge). They are classified into three types.

1. triglycerides- source of energy
2. phospholipids-responsible for structure of plasma cell membrane
3. Steroid-component of plasma membrane & foundation from which steroid hormones: estrogen and testosterone are made

Question 23

What are prokaryotic cells?

Answer 23

Cells that lack a membrane-bound nucleus
• structurally more simple and smaller than eukaryotic cells
• bacteria & group of microscopic organism called archaea (include species that inhabit extreme environments)
• most surrounded by rigid cell wall
• membrane does not surround DNA
• circular DNA
• DNA in cytoplasm

Question 24

What are eukaryotic cells?

Answer 24

cells contain a nucleus and other structures enclosed within membranes.
• cells of plants, animals, fungi, protists and all other organisms except bacteria and archaea
• membrane bound organelles such mitochondria and endoplasmic reticulum
• DNA in nucleus
• plant cells have walls, animal cells do not
• DNA is coiled, linear strands

Question 25

Define unicellular.

Answer 25

some organisms that only have a single cell

Question 26

Multicellular

Answer 26

some organisms that are composed of trillions of cells

Question 27

Describe the different mechanisms of cellular reproduction for prokaryotes.

Answer 27

Prokaryotes:
-binary fission
asexual reproduction by a separation of the body into two new identical daughter cells that are equal in appearance (an organism duplicates its DNA, and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA
-mitosis
A type of nuclear division occurring in somatic cells in which two identical cells, called daughter cells, are generated from a single cell. The original cell first replicates its genetic material and then distributes a complete set of genetic information to each of its daughter cells.

Question 28

Describe the different mechanisms of cellular reproduction for eukaryotes.

Answer 28

Eukaryotes:
-mitosis
A type of nuclear division occurring in somatic cells in which two identical cells, called daughter cells, are generated from a single cell. The original cell first replicates its genetic material and then distributes a complete set of genetic information to each of its daughter cells.
-meiosis 1
-meiosis2
a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.

Question 29

What is metabolism? Give an example.

Answer 29

The sum of all chemical reactions within living cells. Metabolism maintains life and allows organisms to grow.
Ex: digestion

Question 30

What is catabolism? Give and example.

Answer 30

Chemical reactions within living cells that break down complex molecules into simpler ones, releasing energy from chemical bonds

EX: breaking down of glucose to ATP, Polysaccharides to monosaccharaides, lipids to fatty acids, nucleic acids to nucleotides, exercise

Question 31

What is anabolism? Give and example?

Answer 31

The building (synthetic) chemical reactions within living cells, as when cells build complicated molecules from simpler owns.

EX: increases in muscle mass, protein synthesis, cellular respiration

Question 32

Give one example of how an organism responds at a cellular level.

Answer 32

EX: humans and other animals detect with sense organs and respond via nervous system

Question 33

Homeostasis is defined as a dynamic equilibrium-explain what this means using examples.

Answer 33

homeostasis is the ability of living organisms to maintain a relatively constant internal environment in all levels of body organization. The organ systems of the body constantly adjust their functioning in response to changes in the internal and external environment.

It is a dynamic state because homeostatic mechanisms do not maintain a absolute internal constancy, but they do dampen fluctuations around a set point to keep internal conditions within a certain range. So, homeostasis is not a static state but a dynamic one.

EX: maintaining a 37 degree body temperature through cooperation of organ systems

Question 34

Describe examples of positive give the logic of why and when each strategy is necessary.

Answer 34

Positive Feedback: The mechanism by which the outcome of a process feeds back on the system, further stimulating the process.
Ex: the onset of contractions in childbirth- when a contraction occurs, oxytocin causes a nerve stimulus, which stimulates the hypothalamus to produce more oxytocin, which increases uterine contractions. This results in contractions increasing in amplitude and frequency.

Question 35

Describe negative feedback and give an example.

Answer 35

Negative Feedback: corrective measures that slow or reverse a variation from the normal value factor, such as blood glucose level or body temperature and return the factor to its normal value (feedback that turns off response). When normal value is reached, corrective measure ceases.
Ex:EX: increases glucose in blood detected by cells in pancreas that secrete insulin which stimulates liver to take up glucose. Glucagon works n the opposite way. Insulin and glucagon are responsible for remaining homeostasis in the blood.

Question 36

Describe one example of evolution and the factors you think were involved.

Answer 36

Ex: several fossils reveal that whales evolved from terrestrial mammals that returned to water.
Factor: discovery in fossil whales of an ankle bone similar to hoofed animals–> population may have changed over time to adapt to thir environment

Question 37

What is natural selection?

Answer 37

1.populations could increase exponentially
2.natural populations usually don’t
3.because resources are limited
–thus: there is a struggle for existence amongst individuals of populations
4.Individuals are not identical, but vary
5.Variation is heritable
Since: survival depends in part on heritable characteristics
–Therefor unequal survivorship will lead to a gradual change in the population, with favorable characteristics accumulating over generations

Question 38

Outline the major hominid species and the evolutionary feats accomplished by each.

Answer 38

1.Australopithecus
Ardepithecus- bipedalism
2.Homo Habilis-tool use, speech
3.Homo Erectus-Fire, migration
4.Homo Neanderthalensis-buried their dead
5. Homo sapiens-domestication of animals, agriculture

Question 39

Explain the statement “evolution is the interactions between genetics and the environment.”

Answer 39

A population organisms change in some way to respond to the environment.
The genetics of a population shift (not just and individual organism) over time to adapt to environmental circumstances. It is more of a bush not a linear progression & some coexist.

Question 40

Give 4 different strategies for understanding Macroevolution?

Answer 40

1. Genetic Drift-allele freq of pop change randomly by chance
2. Gene Flow-individuals move in and out of pop
3. Mutation-changes in DNA of gene-new alleles, new change to gene pool
4. Natural selection-individuals with greater fitness produce successful offspring and these genes are represented in future generations

Question 41

How are the three domains of life related? Give some evidence with your answer.

Answer 41

all have dna

• they are related because inorganic molecules form small organic molecules
• small organic molecules join to form larger ones
• possible that large organic molecules including RNA, small proteins aggregate in droplets
• droplets eventually form true prokaryotic cells
• eukaryotic cells arise
• multicellular eukaryotic organisms

Question 42

How did eukaryotic organelles originate?

Answer 42

1. They originated from prokaryotic ancestors
2. nucleus and many organelles originated from infolding of cell membrane
3. some organs form endosymbiosis (one of the symbiotic organisms lives inside the other.)
4. chloroplasts originated in similar endosymbiotic manner and quite possibly other organelles too

Question 43

What is the evidence for endosymbiotic hypothesis? If you were a new graduate student and wanted to show, without a doubt, that the endosymbiotic hypothesis was true- what piece of evidence would you find most convincing?

Answer 43

1. mitochondria may have been free living bacteria (have own dna)
2. prokaryotic fossils show that they used metabolism without oxygen for photosynthesis and then engulf other cells for oxygen for a mutually beneficial relationship where they were able to get energy from oxygen

Question 44

Describe the phospholipid bilayer. What features make it so essential for life.

Answer 44

Glycerol is bonded to 2 fatty acids and a phosphate group. The region made up of fatty acids is nonpolar and hydrophobic. The other region is polar and is hydrophilic. The hydrophilic heads and hydrophobic tails are responsible for the structure of plasma cell membranes. Phospholipids are arranged in a double layer called a bilayer with hydrophilic heads of each layer facing away from each other. Surface consists of hydrophilic heads in contact with water solutions inside and outside cell. The hydrophobic tails of the two layers point toward each other and help hold the membrane together.
 forming a membrane that can only be penetrated by certain types of substances. This gives the cell a clear boundary, and keeps unwanted substances out.
 permeable to nonpolar hydrophobic molecules impermeable to polar hydrophilic molecules
 membrane proteins act as gatekeepers and pumps

Question 45

Outline 3 ways to get an impermeable molecule across the bilayer.

Answer 45

1.Active transport: the movement of molecules across the plasma membrane, usually against a concentration gradient (from a region of lower concentration to one of higher concentration) with the aid of a carrier protein and energy (usually in form of ATP adenosine triphosphate) supplied by the cell
2.Facilitated Transport/Diffusion: The movement of a substance from a region of higher concentration to a region of lower concentration with the aid of a membrane protein that either transports the substance from one side of the membrane to the other or forms a channel through which it can move
3. Osmosis: A special case of diffusion in which water moves across the plasma membrane or any other selectively permeable membrane from a region of lower concentration of solute to a region of higher concentration of solute.
Channel proteins:
aquaporin →protein that sits in the membrane. Its function is facilitated transport→ allows movement of water cells to pass through the plasma membrane → water can go in and out
Sodium potassium pump→moves NA+ out of cell and concentrates k+ in the cytoplasm

Endocytosis:

Exocytosis-

Question 46

A subset of the organelles are somehow connected. Explain which organelles are connected and how.

Answer 46

Nucleus and rough ER synthesizes proteins goes to golgi apparatus and they do something with it that makes a lysosome→ lysosome digests damaged organelles release products or digest food fat→ second piece of evidence endomembrane system is one unit

Question 47

Two diseases were described that are protein storage disorders. Explain what they are and how you think that excess protein can lead to cell death.

Answer 47

1.Parkinson’s disease is associated with accumulation of mis-folded protein.
2.Alzheimers- protein mis-folding disease
• rough Endoplasmic Reticulum synthesizes proteins that fold into 3° structure
 in the ER→ Misfolded proteins accumulate and can lead to cell death

Question 48

What is inductive reasoning?

Answer 48

-a logical progression of though proceeding from specific to general.
-It involves the accumulation of facts through observation until the weight of evidence forces some general statement about the phenomenon.
A conclusion is reached on the basis of a # of observations & if universal then it is a law

Question 49

What is deductive reasoning?

Answer 49

• a logical progression of thought proceeding from the general to the specific
• it involves making specific deductions based on a larger generalization or premise.
• the statement is usually in the form of an “if…then” premise
• hypothesis testing is deductive reasoning, going from general concepts to specific explanations, and testing the explanation
• if well accepted and general–> then is a theory