AP Biology Practice Test


The revised AP Biology course is focused on enduring, conceptual understandings and content that supports these understandings. The emphasis of the course is on learning essential concepts and reasoning skills. It is the equivalent of a two-semester college introductory class. Our free AP Biology practice test is a great place to start your exam prep.

AP Biology Multiple Choice Questions

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Question 1
Sodium has an atomic number of 11, therefore it is possible to predict that a sodium atom has _____.

A
11 neutrons
B
11 protons
C
11 electrons
D
8 electrons in its outermost shell
E
B and C only
Question 1 Explanation: 
The number of protons is equal to the atomic number. The number of protons in a neutral atom is always equal to the number of electrons. The mass number of the element is needed to calculate the number of neutrons.
Question 2
Hydrogen bonding in a water molecule leads to produce which properties in water?

I. Cohesion

II. Surface tension

III. Creation of a polar molecule

A
I only
B
II only
C
I and II only
D
II and III only
E
I, II and III
Question 2 Explanation: 
Water is unique because it is a polar molecule. This occurs when highly electronegative oxygen creates an unequal distribution of charges when it bonds with hydrogen. Water is cohesive and has high surface tension because oxygen will readily seek to bind with hydrogen as soon as the hydrogen bond is broken.
Question 3
Which of the following would be considered a polypeptide?

A
Starch
B
Glucose
C
Fructose
D
Protein
Question 3 Explanation: 
Starch is a polysaccharide, or molecule made up of many subunits of smaller sugars. Glucose and fructose are simple (small) sugars. Protein is comprised of amino acids and not sugar. Protein is considered to be a polypeptide because it is made of amino acids.
Question 4
The bonding of two sugars to form a larger molecule requires which of the following?

A
the addition of a water molecule
B
the removal of a water molecule
C
the formation of a hydrogen bond
D
the formation of a hydrogen bond
E
none of these choices
Question 4 Explanation: 
Water must be removed to create both polysaccharides and polypeptides through a condensation reaction. Water is removed from the two sugars and the result is a bond that helps to form long strands of sugar molecules, one at a time.
Question 5
Which organelle is NOT found in a prokaryotic cell?

A
DNA
B
Smooth endoplasmic reticulum
C
Plasma membrane
D
Ribosomes
E
Cell wall
Question 5 Explanation: 
The smooth endoplasmic reticulum is an integral part of the synthesis of molecules in the cell. It also serves as a transport system in the cell. It is not however, found in a prokaryotic cell. A prokaryotic cell is simple and does not contain organelles.
Question 6
Which organelle is responsible for releasing hydrolytic enzymes that can help to destroy cellular debris?

A
Vacuole
B
Chloroplast
C
Lysosome
D
Ribosome
E
Peroxisome
Question 6 Explanation: 
A lysosome is a very special organelle. It contains hydrolytic enzymes that can break down cellular debris or other wastes in the cell. They are the only storage component in the cell with these types of enzymes.
Question 7
The structure labeled letter “E” in the diagram below is:

bio

A
A glycoprotein
B
Head of a phospholipid
C
Tail of a phospholipid
D
A membrane protein
E
A gated ion channel
Question 7 Explanation: 
Letter E is pointing to the hydrophobic tail of a phospholipid. It is an integral part of the semi-permeable membrane that makes up the cell membrane.
Question 8
Which step of cellular respiration will generate ATP regardless of whether oxygen is present or not?

A
Krebs Cycle
B
Oxidative phosphorylation
C
Glycolysis
D
Electron transport chain
E
Lactic acid fermentation
Question 8 Explanation: 
Glycolysis is the first step in cellular respiration when glucose is broken down to create ATP. It is a process that does not require oxygen to take place. Glycolysis is an aerobic process, therefore, the presence of oxygen has no effect on its ability to run.
Question 9
The oxygen that is given off by plants as a by-product is derived from _______.

A
Carbon dioxide
B
Water
C
Protein
D
The sun
E
Cellular respiration
Question 9 Explanation: 
Water is absorbed by the roots of a plant. It is then sent to the leaves of a plant – the site of the light reactions. When water is split it begins the light reactions and allows electrons to flow down the electron transport chain.
Question 10
A scientist shined a green light on a plant for a period of two weeks and gave it plenty of water.  At the end of two weeks the plant looked as though it were about to die.  The likely reason for the declining health of the plant is:

A
The plant could not perform photosynthesis.
B
The plant had a disease that caused its demise.
C
The plant did not have sufficient nutrients.
D
The plant absorbed too much green light.
E
The reason for the plant’s demise is not listed.
Question 10 Explanation: 
The plant could not perform photosynthesis. A plant can usually absorb the colors purple, blue and red well. However, the reason that plants appear green to us it because they reflect green. This plant had been unable to utilize photosynthesis because all of the green light was reflected.
Question 11
Which of the following occurs during anaphase of mitosis?

A
DNA is synthesized
B
Chromosomes condense
C
The cell contains double the amount of chromosomes for a short time.
D
Centrioles separate
E
Chromosomes undo their condensing
Question 11 Explanation: 
Until the cells fully complete anaphase there are two copies of the genetic material. During anaphase the mitotic spindle attached to the centrioles will pull apart the chromosomes. Then each cell will be ready to divide as they will have the correct amount of DNA.
Question 12
During which phase of meiosis is a nondisjunction most likely to occur?

A
Interphase
B
Prophase
C
Metaphase
D
Anaphase
E
Telophase
Question 12 Explanation: 
A nondisjunction is the failure of chromosomes to separate properly in anaphase. When the chromosomes fail to separate properly there will be an incorrect number of chromosomes in the resulting gametes. This leads to some genetic disorders like Down’s syndrome.
Question 13
Two plants with pink flowers are mated in a genetic cross.  The F1 progeny ratio is:  1 red: 2 pink: 1 white.  What is the best reason for this distribution of colors in the progeny?

A
Incomplete dominance
B
Codominance
C
Independent assortment
D
Nondisjunction
E
Mutation
Question 13 Explanation: 
This is a case of incomplete dominance. In incomplete dominance there is a blending of the two phenotypes of the parent. The carrier progeny display a mix of both parents (in this case pink). When the two carriers are crossed (Rr X Rr) there is a mix of phenotypes displaced. RR (red), Rr (pink) and rr (white) are all possible phenotypes from a cross between carriers.
Question 14
What enzyme is responsible for joining Okazaki fragments in DNA replication?

A
Helicase
B
Ligase
C
Polymerase
D
Primase
E
Amylase
Question 14 Explanation: 
Ligase is a glue like substance that will anneal (join) the short fragments that occurring on the lagging strand during DNA replication. These short fragments are then joined to become a complementary and continuous part of the new DNA molecule.
Question 15
The only nitrogenous base that is missing in RNA is known as:

A
Adenine
B
Guanine
C
Cytosine
D
Thymine
E
Uracil
Question 15 Explanation: 
In RNA, thymine is replaced by uracil. Adenine will form a bond with uracil. As a result, there are no thymine nucleotides in RNA.
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Next Practice Test:
AP Biology Practice Test 2>>

About the AP Biology Test:
The AP Biology test is divided into two sections.  Section I is multiple choice and Section II is free response. You have 90 minutes to complete each section, and each section will account for half of your grade.

Part A of Section I consists of 63 multiple choice questions. Part B of Section I consists of 6 grid-in questions, in which you will need to integrate your math and science skills in calculating the correct answers. After solving the problem you will write in (or “grid-in”) the exact answer that you have calculated.

Section II begins with a 10 minute reading period. You will then have 80 minutes to answer 2 long free response questions and 6 short free response questions. Students are allowed to use simple four-function calculators on the entire exam.

Get started on your exam prep right now with our free AP Bio practice tests. They feature challenging questions with instant scoring, along with thorough explanations for the correct answers.