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Biology Semester 1 Study Guide
Why Do We Study Science?
● for personal reasons
● To understand how the world and universe works
● To learn how to approach and solve problems
● To learn how to find answers to our questions
● To improve the quality of our lives
What makes a good scientist?
● Someone who questions the world around them
● Someone who uses objective thinking
● Someone with good reasoning skills
What is an Observation?
Using 1 or more senses to describe the things you see.
There are 2 Types of Observations
1. Quantitative: Measureable observations. Observations made with instruments such as
rulers, balances, thermometers, etc. Example: There are 10ml of water in the beaker.
2. Qualitative: observations made using your senses (sight, smell, touch, taste, hear)
Example: The water is clear.
What is Objectivity?
Using only FACTS to describe observations
What is Subjectivity?
● When you include personal opinions or make assumptions while making an observation
● It is the opposite of Objectivity
Why is it important for scientists to be Objective?

If scientists are not objective they will make incorrect observations that are based on opinions or
assumptions rather than facts and evidence
Inferences and the Scientific Method
-
Inference: explaining or interpreting an observation. Inferences must be reasonable and based
on evidence.
Scientific Inquiry: the diverse ways scientists study the natural world and propose explanations
based on the evidence that they gather
What are the 6 basic elements of the Scientific Method?
1. Observation
2. Question or Problem
- This is written in the form of a question.
Example: Which of these two paper towel brands will absorb more water?
3. Form a Hypothesis
-
A hypothesis is a possible answer to your question. It is usually based on the inference
made from the observation!
- It is a testable statement (more on this later…)
Example: If brand A is thicker than brand B, then brand A will absorb more water.
4. Perform an Experiment to test the hypothesis.
Example: How would you test which paper towel will absorb more?
 Spread out a certain amount of liquid
 Use the paper towel to pick up as much as you can
 Measure how much is left over
5. Analyze the Data
- Includes creating tables or graphs to look for trends.
6. Draw a Conclusion
- Here you look at the data from the experiment to see if your hypothesis was correct or
incorrect.
What is a Hypothesis?
-
-
A hypothesis is a possible answer to your question. It is usually based on the inference
made from the observation!
- It is a testable statement (more on this later…)
Hypothesis: is a prediction about the outcome of a scientific investigation. They are based on a
person’s observations and previous knowledge or experience
What are the characteristics of a good Hypothesis?
-
Testable
Make a prediction
Written in an If…then…because statement form.
How are hypotheses written?
As an If…Then… statement.
-
this shows a cause and effect relationship
Example: If I wash my dog, Then he will be clean Because the water and shampoo will
remove all of the dirt.
Model:
1. If I give my plants fertilizer, then they will grow as big as my neighbor’s plants, because that is
what my neighbor does.
- Testable and properly worded
2. If I get lucky, then my plants will grow bigger because that is how luck works.
- not testable, can’t test “getting lucky”
3. My plants aren’t growing bigger because I don’t water them enough.
- Not worded properly.
What are variables?
-
Variables:
o Root: Vary
o Vary means to change
Constants (or control variables): keeping all conditions of the experiment the same except for
the variables you are testing.
Variable: factors that change.
o Independent Variable: the variable that you purposely change and test.
o Dependent Variable: the factor that may change as a result of your independent variable.
-
Example: You want to answer the questions: Will houseplants grow faster if you make the
room warmer? To answer this question, you decide to grow the plants at different
temperatures.
o Independent variable: the temperature of the room
o Dependent variable: how fast plants grow
o Constants (controlled variables): size of container, type of soil, amount of water, amount of
light exposure, use of fertilizer.
What are the three parts of the Cell Theory?
1. All living things are composed of cells.
2. Cells are the basic units of structure and function in living things.
3. All cells are produced from other cells.
What are the different levels that life can be broken down into?
Atoms → Molecules → Organelles → Cells →Tissue →Organs → Organ Systems → Organisms → Populations →
Community →Ecosystems → Biome → Biosphere
Prokaryotes vs. Eukaryotes
How can all cells be classified ?
-
All cells can be divided up into two main categories: prokaryotic cells and eukaryotic cells.
Although these cells have some distinct differences, these cells are more alike than they are different.
What do all cells have in common?
o
o
o
o
o
All cells contain DNA.
DNA is the genetic material that determines everything about cells.
All cells also are covered by a cell membrane. This helps the cell regulate what substances come in
and out of it.
All cells are also made from the same basic chemicals: carbohydrates, proteins, nucleic acid,
minerals, fats and vitamins.
Finally, all cells have ribosomes that are used to make proteins.
How do Prokaryotic and Eukaryotic cells differ?
o
o
Prokaryotes
 No nucleus – DNA floats freely
 Much more simplistic (primitive)
 Much smaller than eukaryotes
 Example: bacteria
Eukaryotes
 Contain a nucleus that stores the DNA
 Contain organelles (little organs) with membranes
 Capable of more complex functions
 Examples: Animals, plants, protists, etc.
What are the functions of the organelles that make up the cell?
Cell Membrane:
1. Separates the cell from its surroundings
2. Selectively permeable
3. Plant and Animal Cells
Cytoplasm:
1. Fluid that fills the cell
2. Keeps organelles in place
3. Plant and Animal Cells
Endoplasmic Reticulum:
1. Maze-like structure around the nucleus
2. Helps transport proteins throughout the cell.
3. Plant and Animal Cells
Ribosomes:
1. Small dot-like structures
2. Create Proteins.
3. Plant and Animal Cells
Mitochondria
1. Small bean-shaped structure
2. Produces energy for the cell
3. Plant and Animal Cells
Nucleus:
1. Stores DNA/genetic information
2. Controls all functions of cell
3. Plant and Animal Cells
Golgi Apparatus:
1. Packages proteins to send throughout the cell
2. Looks like a stack of pancakes or tubes
3. Plant and Animal Cells
Lysosomes:
1. Breaks down food and old cell parts for use
throughout the cell
2. Plant and Animal Cells
Cell Wall:
1. Gives cells structure and support
2. Outermost, rigid layer around plant cells
3. Plant cells and some Prokaryotic Cells (eg
Bacteria)
Vacuole
1. Stores materials and wastes in the cell
2. Looks like a large water-filled sac
3. Plant and Animal Cells (significantly larger in
Plant cells)
Chloroplasts:
1. Place where photosynthesis (converting of
sunlight to food energy)
2. Small green structure
Locate the Organelles in both a Plant and Animal Cell
Why is Photosynthesis important?
Photosynthesis is the process that allows all living things on earth to acquire the energy that they needed
Where does energy come from?
•
Nearly all living things obtain their energy either directly or indirectly from the energy of sunlight.
•
Autotrophs (organisms that produce their own food) capture the energy of sunlight and store it in a
process called Photosynthesis.
•
Then heterotrophs (organisms that consume other plants or animals) eat either the plants themselves or
other organisms that have eaten the plants to obtain that energy.
What is Photosynthesis?
•
Photosynthesis is a chemical reaction that takes place in the chloroplasts of plant cells.
•
During photosynthesis, plants use the energy of sunlight to produce energy-rich molecules called
carbohydrates.
Where does Photosynthesis take place?
In the chloroplast of plant cells
How does Photosynthesis occur?
•
Photosynthesis happens in two stages.
•
Stage 1: Chloroplasts capture sunlight and turns it into energy.
•
Stage 2: Plant cells use energy from stage 1 as well as hydrogen (H) and carbon dioxide (CO2) to
produce sugars such as glucose.
What happens during the first stage of photosynthesis?
In the first stage of photosynthesis plants use chlorophyll to capture light.
-
Chlorophyll is found in chloroplasts.
Chlorophyll is a pigment—a colored compound that absorbs certain colors of light but not others.
Chlorophyll is green, it is what gives plants their color.
Stage 1 of photosynthesis:
1. Chloroplasts capture energy from the sun
2. 2H20  4H+ + O2
What happens during the second stage of photosynthesis?
-
In the second stage of photosynthesis, cells produce sugars.
The Hydrogen from stage one and carbon dioxide (CO2) from the air combine to create an important
sugar called glucose (C6H12O6).
Sugars are a type of carbohydrate. Carbohydrates are a vital source of energy for autotrophs and
heterotrophs alike.
What is the chemical equation that represent photosynthesis ?
Water
Carbon Dioxide
What are the components on the left hand side of the equation called?
Reactants (raw materials)
What are the components on the right hand side of the equation called?
Products
Glucose
Oxygen
During which stage of photosynthesis is oxygen produced?
Stage one
What are the products of photosynthesis?
Glucose and oxygen
What are the reactants (raw materials) needed for photosynthesis?
Water and Carbon Dioxide
How are photosynthesis and cellular respiration different?

Cellular respiration is the reverse of photosynthesis (chemical equation written in the opposite direction)
with energy being released

Cellular respiration takes place in the mitochondria of both plant and animal cells

Photosynthesis takes place in the chloroplast of plant cells only
Semester 1 Biology Study Guide
Practice Questions
Directions: Read each of the following questions and circle the best answer choice.
1. Which of the following is NOT a reason that we study science?
a. To gain a better understanding of the how world around us works.
b. To help us learn to solve problems and answer questions
c. To discover new ways to improve people’s lives.
d. To mix chemicals and make them explode.
2. Which of the following conclusions would an objective scientist make?
a. The water in the river looks dark and cloudy. It must contain toxic chemicals and not be
safe for swimming.
b. I saw a robin add a piece of yarn to his nest. The rest of his nest is made of pine needles.
Robins must use both natural and man-made objects to make their nests.
c. That soup looks gross and it was made by my mother. Most things that look gross and are
made by my mother taste awful. This soup must taste disgusting too.
d. When I was in the park today, I saw a squirrel carry a nut to a tree. I think he took it there
so he could eat it. Squirrels must only eat nuts.
3. What is it called if I use my senses to gather bits of information?
a. inference
b. science
c. hypothesis
d. observation
4. What is the difference between an observation and an inference?
a. An observation is quantitative and an inference is qualitative.
b. An inference is more specific than an observation.
c. An inference proposes why something occurs and an observation tells what occurs.
d. An observation proposes why something occurs and an inference tells what occurs.
5. Which of the following is NOT a characteristic of a good hypothesis?
a. A good hypothesis is based on observations and inferences.
b. A good hypothesis is in the form of a statement and explains a cause/effect relationship.
c. A good hypothesis is testable and falsifiable.
d. A good hypothesis is based on a subjective observation.
6. Which of the following is an example of a good hypothesis?
a. A bicycle with fenders will keep a rider drier when they ride through a puddle than a
bicycle that does not have one.
b. If my dog could talk, then he would tell me when he was hungry.
c. Ladybugs are a good natural pesticide for treating aphid infected plants.
d. If I never water my plant, then it will dry out and die.
7. How do scientists generate good questions?
a. They ask other scientists for ideas.
b. They consider what they observe and ask why it is occurring.
c. They look at other questions and come up with their own.
d. They ask themselves, “What do I see happening?”
8. Which of the following steps to solve a problem must be completed first?
a. analyzing data
b. recognizing and identifying the problem
c. forming a hypothesis
d. testing a hypothesis
9. In which of the following scenarios did the scientist NOT follow the steps of the
scientific method to investigate a topic?
a. A scientist observed ants in his kitchen and wondered what they were looking for. Noting
that they were in the kitchen and reading that ants were often called “picnic pests”, he
proposed that they were looking for food. He designed an experiment where he placed an
ant directly between two plates: one that contained food and one that contained no food.
He recorded the number of times it approached the plate with the food. After watching the
ant approach the food 9/10 times, he concluded that his results seemed to support his
hypothesis.
b. A scientist who likes to garden noticed that some tomatoes were bigger than others and
wondered why. After researching the topic, he learned that the amount of sunlight can
affect how plants grow. He proposed that the more sunlight a tomato plant receives, the
larger the tomatoes will grow. He planted one plant in the shade and one plant in the sun.
After they grew, he measured them and found that the ones from the plant in the sun were
3-6 centimeters bigger than the ones in the shade. He concluded that his results seemed to
support his hypothesis.
c. A scientist was frustrated when he could not bake cookies because his oven was broken. He
decided to experiment and see if the oven was working or not the next five times he
wanted to make cookies. After a week, he decided that he had proved his hypothesis
because the oven was broken each of the days he wanted to bake cookies.
d. A scientist bought a new pair of shoes that claimed to make him faster. He wondered if this
was true. After researching information on how shoes help people run, he proposed that
these new shoes would make him faster than his old shoes. He ran a mile in his new shoes
and a mile in his old shoes, recoding the amount of time it took him. Both times it took him
9:00 minutes. He concluded that his results did not seem to support his hypothesis.
10. According to question 9, why was the scenario you chose not a representation of the scientific
method?
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Questions 11-14 refer to the following investigation:
Hypothesis:
If I add salt to water, then the water will take less time to boil.
Procedure:
Two pots with equal amounts of water were placed on a stove. Two teaspoons of salt were added
to one of the pots. The temperature of the water was recorded every 30 seconds until it reached
the boiling point of 100 ⁰C. The results are shown in the tables below.
Pot 1 (no salt)
Temperature
Time (s)
(⁰C)
120
70
Pot 2 (salt)
Temperature
Time (s)
(⁰C)
120
80
150
180
210
240
270
300
150
180
210
240
270
300
80
85
90
95
97
100
90
98
99
100
100
100
11. What was the independent variable in this investigation?
a. presence of salt
b. amount of water
c. temperature
d. time
12. What was the dependent variable?
a. presence of salt
b. amount of water
c. temperature
d. time
13. What was a control variable?
a. presence of salt
b. amount of water
c. temperature
d. time
14. Given the data presented, which of the following would be a logical conclusion to draw?
a. The results of the experiment indicate that the presence of salt does not seem to affect the
amount of time it takes for water to boil
b. The results of the experiment indicate that the presence of salt does seem to encourage
water to boil faster.
c. The results of the experiment indicate that the presence of salt seems to cause the water to
boil slower.
d. The results prove the hypothesis.
15. All of the following are characteristics of a replicable procedure except…
a. includes a general description of what happens in the experiment
b. written as a numbered list of steps
c. includes all materials needed
d. uses specific, detailed commands
16. Why is it important that scientists’ work be replicable?
a. So that hypotheses can be tested and revised.
b. So that other scientists can perform the experiment.
c. None of the above.
d. Both a and b.
17. Which of the following procedures is written so that it is easily reproduced?
a. Pour 32 ml of water in a beaker. Add 20 drops of yellow food coloring. Mix using an electric
stirrer for 25 seconds.
b. Pour water in a beaker. Add food coloring. Stir.
c. Mix water and food coloring together.
d. None of the above would be easy to reproduce.
18. In a controlled experiment, a scientist is studying how long it takes parachutes of different sizes to
fall to the ground. What is the independent variable?
a. the size of the parachute
b. the height from which the parachute is dropped
c. the size of the object carried by the parachute
d. the time it takes for the parachute to drop
19. What is experimental bias?
a. When a scientist performs the wrong experiment.
b. When one or more of the variables are not properly controlled.
c. When a sample size is not large enough to accurately represent a conclusion.
d. When a scientist makes a measurement error.
e.
20. What type of bias is presented in the following experiment?
Ms. Jackson is making observations at Woodlawn High School to investigate the rate of smoking
among American teenagers. Ms. Jackson decides she will observe students having their lunch in
the parking lot where smoking is permitted. Ms. Jackson observes 25 out of 30 students smoking
in the parking lot. Based on her observations she records that 83.3% of American teenagers
smoke.
a.
b.
c.
d.
Experimental bias
Sampling bias
Measurement error
No bias
21. How could you change the design of the experiment from question 20 so that it reduces
bias? (____/1 point)
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22. Which of the following conclusions would NOT be acceptable in science?
a. The results support the hypothesis.
b. The results prove the hypothesis.
c. The results do not support the hypothesis; thus it is rejected.
d. All of the above are acceptable conclusions.
23. How many independent variables should a science investigation contain?
a. one
b. two
c. zero
d. as many as possible
24. Which of the following best describes the dependent variable in an experiment?
a. Something that remains the same
b. Something that the scientist changes
c. Something that makes the experiment reliable
d. Something that the scientist measures
25. What is the best way for a scientist to ensure that he or she collects reliable data?
a. Record data in an organized data table, and use it to create a graph
b. Only use subjects that agree to participate in the experiment
c. Conduct multiple trials of an experiment
d. Discard any data that does not fit with the hypothesis
26. What step would a scientist most likely take after performing multiple trials of an experiment?
a. Discard data from some trials
b. Make a hypothesis about the investigation
c. Write a conclusion to the investigation
d. Average the data from all trials
27. What is the difference between reliable data and valid data?
a. Valid data is reproducible and reliable data is relevant to the experiment
b. Valid data only comes from one trial and reliable data comes from multiple trials
c. Reliable data refers to quantitative data and valid data refers to qualitative data
d. Reliable data is reproducible and valid data is relevant to the experiment
28. A scientist is investigating which brand of battery lasts longest in a digital camera. Which of the following
data is valid for this experiment?
a. The length and width of the battery
b. The color of the battery
c. The number of hours the battery can power a digital camera
d. The age of the battery
29. Ms. Ange wants to determine how long it takes a yellow rose to fully bloom. She goes to Frank’s Flower
Shop, buys one, closed yellow rose and places it in her kitchen window. She observes that it takes the rose 92
hours to fully bloom. Why can Ms. Ange not make a scientific conclusion from this data?
a. It is not reliable data.
b. It is false data.
c. It is untested data.
d. The experiment has no independent variable.
30. Dr. Douglas wants to test if students receive higher grades in the morning or in the afternoon. She gives 5
ninth grade students a vocabulary test during first period and then gives the same 5 students another vocabulary
test during seventh period. Which of the following is the sample size for this experiment?
a. The scores the students receive on the tests
b. The number of trials that she performed
c. The number of students that she tested
d. The grade the students are in
Questions 31-33 refer to the data table on the left.
31. What would be an appropriate title for this data
table?
a. The Effect of Time on Volume
b. The Effect of Volume on Time
c. Volume Vs. Time
d. Time vs. Volume
Volume of Water
30 ml
40 ml
50 ml
60 ml
Time it Takes to Boil
5 minutes
6 minutes
7 minutes
8 minutes
32. If you were to use a graph to represent this data, what kind of graph would you choose?
a. Line graph
b. Bar graph
c. Scatter plot
d. Pie chart
33. Why is this type of graph most appropriate for the data set?
a. The scientist wants to show how something changes over a short period of time.
b. The scientist wants to show how something changes over a long period of time.
c. The scientist wants to make comparisons between multiple groups.
d. The scientist wants to show parts of a whole.
34. Which of the following BEST explains the importance of a controlled experiment?
a. Controlled experiments allow scientists to draw accurate conclusions about their data.
b. Controlled experiments allow scientists to test their hypothesis.
c. Controlled experiments allow scientists to accurately test the relationship of their independent
and dependent variables.
d. Controlled experiments are biased and do not
give scientists accurate information.
35. Create a table for the following experimental question
and data: Question: Does the day of the week affect the
number of pizzas sold?
- Monday: 70 pizzas sold
- Thursday: 100 pizzas sold
- Tuesday: 30 pizzas sold
- Friday: 80 pizzas sold
- Wednesday: 40 pizzas sold - Saturday: 10 pizzas sold
For questions 36-38 use the following scenario and graph:
A pizza chain decided to see how many pizzas they sold in 6 days.
They recorded their results in the bar graph below. Use this
graph to answer the following questions.
36. What is the independent variable represented on this
graph? ____________________________
37. What is the dependent variable represented on this graph?
____________________________
38. Write one sentence to describe the relationship between the number of pizzas sold and the day of
the week.
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Questions 30-40 refer to the scenario below.
You keep ants in a plastic ant farm. Yesterday, all of the ants died. You wonder if it was because they were allergic
to their food. To test your hypothesis, you buy a new, larger ant farm made out of glass and begin feeding the ants a
new brand of ant food. After a week, you notice that all of your ants are still living.
39. Which of the following describes the MAIN problem with this experiment?
a.
b.
c.
d.
No dependent variable
Too many controlled variables
Too many independent variables
Scientific question is not testable
40. How could you revise this experiment so that it provides valid and reliable data?
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41. Which of the following inventions was essential to the development of cell theory?
a. pasteurization
b. the microscope
c. the magnifying glass
d. the flask
42. Which of the following is NOT part of cell theory?
a. Cells come only from existing cells.
b. All cells are exactly alike.
c. Cells are the basic unit of structure and function in an organism.
d. All living things are made up of one or more cells.
43. Which of the following
diagrams shows a prokaryotic cell?
a. Diagram 1
b. Diagram 2
c. Diagram 3
d. All of the cells shown are
eukaryotic cells
Diagram 3
Diagram 2
Diagram 1
44. Which of the following is NOT a difference between eukaryotes and prokaryotes?
a) Prokaryotes lack a nucleus.
b) Eukaryotes have membrane-bound organelles.
c) Eukaryotes tend to be multicellular, while prokaryotes tend to be unicellular.
d) Eukaryotes are much smaller in size than prokaryotes.
45. What is the function of the nucleus?
I. It controls what enters and exits the cell.
II. It holds DNA.
III. It acts as the control center of the cell.
a) I and II
b) I and III
c) II and III
d) I, II, and III
46. Draw and Label a Bar graph for the following data and experimental question (______/4)
Experimental Question: Which brand of popcorn has the most kernels?
Experimental
Group
Pop Secret
Trial 1
Trial 2
Trial 3
Average
205 kernels
225 kernels
215 kernels
215 kernels
Orville
Redenbacher
190 kernels
180 kernels
170 kernels
180 kernels
220 kernels
222 kernels
218 kernels
220 kernels
Walgreens
Graph
Questions 47-50 refer to the diagram below.
47. What is the main function of the organelle labeled 3 in the figure above?
a. To create proteins for the cell.
b. To provide energy to the cell.
c. To store the cell’s genetic information.
d. To break down substances taken in by the cell.
48. In the figure above, what is the name of the organelle labeled 7 that sometimes has ribosomes on
the outside wall?
a. Vacuole
b. Nucleus
c. Endoplasmic reticulum
d. Cell membrane
49. What is the name of the organelle labeled 5 in the figure above?
a. The cell wall
b. The cell membrane
c. The cytoplasm
d. Endoplasmic Reticulum
50. Which of the following best describes the function of the organelle labeled 8?
a. It converts energy from food molecules into energy the cell can use.
b. It stores energy from food molecules.
c. It stores energy from sunlight.
d. It produces nucleic acids that release energy.
51. The function of a lysosome is to
a. give the cell shape.
b. break down particles and worn out cell parts.
c. store water and food.
d. make proteins.
52. A similarity and difference between plant and animals cells is…
a. both plant and animals cells have mitochondria but only plant cells have a cell wall.
b. both plant and animals cells have chloroplasts but only plant cells have a cell wall.
c. both plant and animals cells have mitochondria but only animal cells have a cell wall.
d. both plant and animals cells have chloroplasts but only animal cells have a cell wall.
53. What happens during stage one of photosynthesis?
a. Chloroplasts capture energy from the sun and the hydrogen in water is separated from the oxygen.
b. Hydrogen and carbon dioxide come together to form glucose.
c. Chloroplasts capture energy from the sun and hydrogen and carbon dioxide come together.
d. Hydrogen and oxygen come together to form glucose.
54. What happens during stage two of photosynthesis?
a. Chloroplasts capture energy from the sun and the hydrogen in water is separated from the oxygen.
b. Hydrogen and carbon dioxide come together to form glucose.
c. Chloroplasts capture energy from the sun and hydrogen and carbon dioxide come together.
d. Hydrogen and oxygen come together to form glucose.
55. Which of the following BEST describes why plants have cell walls?
a. Plants are constantly on the move so the need the extra protection and support.
b. Plants are stationary and need the extra support because they cannot seek shelter.
c. Plant cells do not have cell walls.
d. Plants need extra protection from predators.
56. Throughout the unit we have been comparing the jobs of different cell organelles to the jobs of
different objects or people. Keeping this in mind, explain how a cell membrane is like a window screen.
Your answer should include specific details and be in at least 2 complete sentences.
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