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BIOLOGY MIDTERM EXAM STUDY GUIDE 2011Vocabulary on test (digital flashcards): http://quizlet.com/3981614/midterm-review-flash-cards/
Unit 11. Introduction to Science & Lab
a. What are the steps of the scientific method?i. State the problemii. Formulate a hypothesisiii. Design an experimentiv. Collect Datav. Conclusion
b. What is the difference between:
i. independent variable: Factor in an experiment manipulated or controlled by the
experimenter in order to elicit results.
ii.dependent variable: Factor measured at the end of an experiment, usually recorded in
metric units.
c. Why is a control group important in an experiment? Give an example of a control group in
the Apple Juice Enzyme Lab. A control group is usually trial run in an experiment without the
independent variable used for comparison purposes. It helps to demonstrate the effect of the
independent variable in the experiment. In the Apple Juice Enzyme Lab the control group was
the trial run without any enzymes added to the apple sauce.
d. What is the proper format for a testable hypothesis?
A hypothesis is usually written in an IF...THEN...BECAUSE format. The independent variable is
linked to the IF in the hypothesis and the dependent variable is linked to the THEN part is linked
to the dependent variable, and the BECAUSE is linked to research regarding the experiment. For
example, IF pectinase is mixed with apple sauce THEN more apple juice will be produced in mL
BECAUSE pectinase is an enzyme that breaks down pectin in apple sauce.
e. What does “validity” mean? What types of factors can influence the validity of an experiment?
Validity is related to the accuracy of an experiment or the certainty of the results. If an
experiment is well designed with the constants kept the same, the results will be more valid or
accurate.
f. What is the difference between constants or controlled variables and control group?
Constants are all the factors in an experiment that need to be kept the same. A control group is
a trial run in an experiment without an independent variable for comparison to the other groups.
2. Unit 2 - Ecology Unit 2: Ecology
a. What is the definition of ecology?
The study of the relationship of living organisms to each other
and to their surroundings (environment)
b. What is the difference between biotic/abiotic factors? Give
examples of each.
biotic factors - living factorsexamples - plants, animals, protists, bacteria
abiotic factors - nonliving factors
examples - environmental factors such as habitat or weather
c. Define the following terms:
i. Population- all of the individuals of the same species in an area (for example - all of the
ducks on the pond). a population is always composed of the same species of organisms.
ii.Community- all the populations that live together in an area
iii. Ecosystem- includes the community and the physical factors in an area
(rain, light, soil)
iv. limiting factor- causes population growth to
decrease. density dependent depends on population size
- competition, predation, disease. density independent
DOES NOT depend on population size - weather,
natural disasters
v. carrying capacity- the number of individuals a particular
environment can support
vi. logistical vs. exponential growth.
logistic = S-shaped curve; as resources become limited growth slows or stops
exponential = J-shaped curve; organisms reproduce at a constant rate and occurs
under ideal conditions.
vii. R-strategist vs. K-strategist
R-strategist - rapid development and high reproductive rate; must possess the ability to reproduce
quickly and produce large numbers of offspring; no parental care necessary; short
life expectancy
K- strategist - long life expectancy; production of few offspring; offspring require extended
parental care
d. How do the following affect population size?
i. Birth rates - increase in population sizeii.death rates - decrease in population sizeiii. lifespan - increased life spans will cause populations to grow because individuals
are living longer; decreased life spans will cause populations to decrease in size b/c there
will be few “older organisms”
i.infant mortality - decrease in population; limited number of young individuals
predatory – prey relationships - predator (organism that is doing the hunting) feeds on the
prey (the hunted). population size could go down
e. What is the difference between populations in an undeveloped vs. developed country?
developed country - Usually depicts a country with a
healthy economy, good infrastructure, good access to
healthcare, low birthrates and low deathrates.undeveloped country - Usually describes a country with a poor economy, poor infrastructure, poor
access to healthcare, high birthrates and high deathrates.
f. How does human activity positively and negatively affect our ecosystems. Humans positively
affect the ecosystems by rescuing and supporting endangered animals, reducing pollution,
recycling, reusing resources, and protecting land areas. Humans negatively affect the
environment by polluting, over-developing land, eliminating ecosystems and disrupting food
webs among many other activities.
g. Which country is developed?
United States
h. Which is undeveloped?
Congoi. Which country has a higher birthrate?
United Statesj. Which country has a higher death rate?
Congo
k. Explain how one of the countries would
respond to advancement in technology. If an
undeveloped country introduced important
vaccines such as tetanus among others, it
would reduce infant mortality. If the infant
population had better survival rates, then the
death rates would decrease. As communities
became more confident of their children’s ability to survive in their environment, the birthrate
would also decrease.
l. How can population size be estimated? What are some advantages and disadvantages of each?
i. Direct count : each individual in a population is counted. An example of this is the
census in the U.S. and this occurs every ten years. An advantage is that once a person
is trained to measure census data, it can be implemented by many census workers. A
disadvantage is that it is very time consuming and errors in counting can occur.
ii. Random sampling A small sample of a population is randomly collected and counted.
Then using mathematical formulas the numbers in the sample size is projected to the
entire area in order to calculate the estimate of the population size. An advantage of
random sampling is that only a small sample needs to be counted rather than the entire
population. A disadvantage is that the small sample collected may have a different make-
up from the entire population leading to an over or under estimation.
iii. Capture-Mark-Recapture A small sample of a population is collected and marked
and released. Upon recapture, the proportion of marked and unmarked individuals helps
to estimate the size of the population. The advantage is that only a small sample needs to
be marked and counted and recounted. A disadvantage is that the population can change
in size between captures and lead to over or under estimation errors.
m. Diagrams: population age charts of developed vs. undeveloped countries, logistical and
exponential growth graphs.
Unit 3 Cell Structures & Processes3. Cell Type & Theory
a. What is the difference between eukaryotic and prokaryotic cells?
Eukaryotic cells are larger, complex cells with a nucleus and other membrane-bound organelles.
Examples of eukaryotic cells are plant and animal cells. Prokaryotic cells are smaller, simple cells
without a nucleus or many organelles. An example of a prokaryotic cell is bacteria.
b. What types of organisms are classified as eukaryotic or prokaryotic? Which types of cells are
believed to have originated on earth?
Plant and animal cells are some examples of organisms classified as eukaryotic, while bacterial
cells are classified as prokaryotic. It is believed that prokaryotic cells originated first on earth with
their simplistic structure and small size.
c. What are the three parts of the cell theory?
i. All living things are made of cells.ii. Cells are the basic unit of living things and carry out life activities
iii. All cells come from pre-existing cells.
4. Cell Structures
a. What are organelles? Organelles are small membrane-bound structures found within cells.
Examples include nucleus, mitochondria, ribosomes, endoplasmic reticulum and golgi body
among others. Each organelle has a specific structure and function.
b. For the following organelles, which are present in Animal cells, Plant cells or both? Know the
function of the *organelles.
Organelle Animal Cell Plant Cell
*Nucleus Present present
Ribosome Present Present
*Mitochondria Present Present
Lysosome Present Mostly absent
*Chloroplast Absent Present
Endoplasmic reticulum (rough and smooth) Present Present
Golgi apparatus Present Present
*Centrioles Present Absent
Cytoskeleton Present Present
Cell Wall Absent Present
*Cell membrane Present Present
c. Diagrams: Plant and animal cells
i. Is the diagram below a plant or animal?
(label each)
ii.Label any 4 structures.
Animal Cell Plant Cell: A: Nucleus, B: DNA or genetic
material, C: nucleolus, E: endoplasmic
reticulum, G: central vacuole, I: chloroplast,
J: cell wall, K: cell membrane
5. Osmosis and Diffusion
a. What is diffusion? Movement of a substance from where there is greater concentration to lesser.
Diffusion does not require energy.
b. How is active transport different from passive diffusion? Active transport is the movement
of substances from lesser concentration to greater and therefore requires energy. This can be
compared to passive diffusion which does not require energy and substances move along their
concentration gradient or from a greater concentration to a lesser concentration.
c. What is osmosis? The diffusion of water from a greater concentration to a lesser concentration
across a membrane. This movement does not require energy.
d. Diagram: Cells and Osmosis
A B C
e. Which beaker has a hypertonic solution? Describe what is happening. Beaker C is a hypertonic
solution because there was more water inside the cell and less water and more solute inside
the beaker. Therefore the water moved OUT of the cell shrinking it in size. This is also called
plasmolysis.
f. Which beaker has a hypotonic solution? Describe what is happening. Beaker A is a hypotonic
solution because there is more water outside the cell than inside, therefore the water enters the
cell and the cell swells in size. In animal cells the cell could burst from the increased amount of
water. In plant cells this increase of water volume fills the large central vacuole internal “turgor”
pressure and plant rigidity.
g. Which beaker has an isotonic solution? Describe what is happening.
Beaker B is an isotonic solution because there is an equal amount of water going into and out of
the cell. Therefore the cell does not change in size.
6. Enzymes
a. What is an enzyme?
proteins that catalyze chemical reactions (speed up)
b. How does an enzyme help biological reactions take place? Explain in terms of activation energy.
enzymes lower the activation energy needed to in order for a reaction to occur.
c. Explain how the enzyme and substrate work like a lock and key.
An enzymes active site has a specific shape much like a lock that will only fit a special shaped
key which would be the substrate.
Image of Lock and Key Model
d. How does temperature affect enzyme activity?
Higher temperatures make the molecules in the system move faster. If the molecules are moving
faster, then the chance that an enzyme and substrate collide/combine to participate in a chemical reaction
increases. However, if the temperature goes too high, then the enzyme risks being denatured (losing its
shape). If the enzyme loses its shape, then the substrate will not be able to fit in the active site (the
enzyme and substrate are no longer specific for one another) and the chemical reaction will not be able to
proceed.
e. Explain the purpose of the experiment run during the Apple Juice PBA.
The purpose of the Apple Juice experiment was to determine which enzyme cellulase, pectinase
or combination of the two produced the greatest volume (mL) of apple juice, and were most
cost effective for use by a Connecticut company in the business of making and selling apple
juice.
Independent Variable: Different Enzymes - Cellulase, Pectinase and a Combination of the Two
Dependent Variable: Volume of Juice Produced (mL)
Control Group: Water
Constants or Controlled Variables: Amount of Apple Sauce, Amount of Enzyme/Water Drops,
Time, Mixture Was Stirred, Time the Mixture set in Filter Etc.
7. Cellular Respiration & Photosynthesis
a. Which is the formula that represents respiration and which represents photosynthesis?
Photosynthesis
Cellular Respiration
b. Why do cells need energy?
To carry out all of the functions of a living organism.
Processes such as growth, reproduction, respiration,
excretion, etc, all require energy.
c. What are the end products of cellular respiration?
36 ATP, Carbon Dioxide, and water. d. What is the difference between anaerobic respiration
and aerobic respiration?
The presence/absence of oxygen, the amount of ATP
produced, as well as the final product. Aerobic respiration occurs in PRESENCE of oxygen, produces
36 ATP molecules, carbon dioxide and water.Anaerobic respiration results in the production of 4ATP molecules, carbon dioxide, lactic acid or ethanol.
e. What is fermentation? Which organisms produce alcohol in this process?
Fermentation is a process that occurs in the absence of oxygen (anaerobic) whereby glucose is
converted into carbon dioxide, ethanol and/or lactic acid depending upon the organism carrying
out
the process. In order for ethanol (alcohol) to be produced, YEAST must be present.
f. What types of organisms perform cellular respiration?
All living organisms carry out cellular respiration. All eukaryotic organisms (plants, mammals,
fish, etc.) carry out aerobic respiraiton and certain prokaryotic organisms (bacteria, yeast, etc.)
carry out anaerobic respiration.
g. What is the driving fuel/energy source needed for this reaction to occur?
The driving fuel needed needed for this reaction to occur is glucose (C6H12O6).
h. In what organelle does cellular respiration occur?
Typically, the process of cellular respiration occurs in the mitochondria of the cell. The first step
of
cellular respiration (glycolysis) however, occurs in the cytoplasm of the cell.
i. What does the term glycolysis mean? Explain the steps of glycolysis.
The term glycolysis means “the lysis or splitting of glucose”. Glycolysis begins with the six
carbon
sugar known as glucose. This molecule is split into two three (3) carbon molecules called PGAL.
It is important to note that this initial splitting of glucose requires two (2) ATP molecules to be
“invested” on the part of the cell. Secondly, each PGAL molecules is subjected to a series of
oxidation/reduction reactions resulting in the production of two (2) pyruvate molecules (PGA)
oftentimes referred to as pyruvic acid. As a byproduct of the production of PGA, four (4) ATP
molecules and 2 NADH molecules are produced.
j. What are the end products of photosynthesis?
The end products of photosynthesis are glucose (C6H12O6) and oxygen.
k. What is the driving energy source needed for this reaction to take place?
The driving energy source needed for this reaction to take place is the sun.
l. Why must the light reactions occur prior to the dark reactions?
The light reactions must occur prior to the dark reactions because this is where the light energy
from the sun is “trapped” by the molecules ADP and NADP+. These two energy transfer
molecules are responsible for delivering this trapped energy to the dark reactions so that the
synthesis of glucose can occur. Without the light reactions, there would be no energy
available in the dark reactions to make glucose.
m. In what organelle does photosynthesis occur? In which part of the plant does the majority of
photosynthesis take place?
Photosynthesis occurs in the chloroplast of plants. The majority of photosynthesis takes place in
the leaves of plants.
n. Why do certain leaves change colors during the fall?
Certain leaves change color in the fall due to the change in temperature, light intensity, and
the availability of water. When these factors change, the various pigments contained in the
leaves of plants break down and others become visible. Specifically, the chlorophyll
pigments (greens) break down the the others (carotenes, xanthophylls, etc.) become visible to the
human eye.
o. What is the difference between ADP and ATP?
Structurally, the difference between ADP and ATP is the presence of one phosphate group. ADP
contains two phosphates and ATP contains three (thus their names: ADP = Adenosine
DI-phosphate and ATP = Adenosine TRI-phosphate. With respect to the amount of energy
contained in each molecule ATP contains a significantly larger amount of stored energy
due to the presence of a single high energy bond between the 2nd and 3rd phosphate
molecules.
p. When is energy released: when ATP is made or broken down into ADP?
Energy is released when ATP is broken down and is converted into the lower energy form
(ADP).
q. Which process makes more ATP: aerobic cellular respiration or anaerobic cellular respiration?
Aerobic Respiration (Glycolysis, Krebs Cycle, Electron Transport Chain) generates a net yield of
36 ATP per glucose molecule. Anaerobic respiration (Glycolysis/Fermentation) only yields a net
of 2 ATP.
Unit 4: Microorganisms1. What are some of the different bacterial shapes?
Round - cocci, Rod - bacillus, Spiral - spirillum. Bacterial colonies (more than
one bacterium) are named in a pre-fix form based on their arrangement. Clumps
are called staphlyo-, chains are called strepto-, and pairs of two are called diplo-.
2. Are bacteria prokaryotic or eukaryotic? Explain.Bacteria are prokaryotic cells because they are very small in size (usually 1-2
micrometers) and do not have a nucleus.
3. How do antibiotics work? Which cell part do they target?
Antibiotics are only effective against bacteria. Many antibiotics (including the first discovered penicillin) target
the bacterial cell walls making it impossible for bacteria to divide.
4. How do vaccines work?
Vaccines are small parts of bacteria or viruses that do not cause disease when
injected into the host but start an immune response to protect the host against
future infections of the bacteria or virus. Vaccines only prevent infectious disease,
they can only be used before the illness is contracted.
5. How do bacteria respond to an unfavorable environment?
Many bacteria can form an endospore which enables the bacteria to survive in a harsh
environment. For example, an “anaerobic bacteria” normally grows only when oxygen IS NOT present.
Therefore, if this bacteria is exposed to oxygen, may form an endospore.
6. What are some ways that bacteria can be controlled?
Bacteria can be controlled with antibiotics. Many antibiotics are selected for a
particular type of bacterial infection and slow down or stop bacterial cell
reproduction.
7. How are bacteria used in the food production industry? Would this be
an example of bacteria being beneficial or harmful?
Bacteria are used to create certain flavors or give foods an acid quality. For
example, cultures of bacteria are used to make yogurt, sauerkraut and some
types of bread. These uses are considered helpful uses of bacteria.
8. Label the following bacteriophage with the terms capsid and genetic
material.
The capsid is the polygon (many sided) shaped head around the DNA or RNA (genetic material) of the
virus. The genetic material is the threads inside of the capsid head being injected into the host cell which in
this case is a bacterial cell called E. coli.
9. What part of the virus allows it to infect a specific host?
Depending on the virus, the capsid-proteins have a unique shape to bind to the host cell.
10. Why are viruses usually NOT considered to be living things?
Viruses are not considered living things because they cannot reproduce on their own but must infect a living
host cell first.
11. What is the difference between a lytic and lysogenic phases?
Both phases may be part of the viral infection cycle. Lytic phase of cycle involves the viral DNA/RNA (genetic
material) infecting the host cell, reproducing viral particle parts, assembling the viral parts, bursting the host cell
and releasing new infectious viral particles. The lysogenic cycle involves the viral DNA/RNA injecting into
the host cell and becoming incorporated into the host cell DNA. The viral genetic material stays within the host
cell’s DNA in this dormant stage, reproducing along with the host. If certain environmental triggers or stress
occur, the lysogenic phase may convert into the lytic or active phase.
12. Provide three examples of both viral and bacterial infections.
Bacterial Infection Viral Infection
1. Strep Throat 1. HIV (AIDS)
2. Salmonella (food poisoning) 2. Herpes
3. Staphylococcus aureus ( can cause skin
infection)3. Common Cold and the Flu