DETAILED ANSWERS|LATEST
UPDATE!!!2025/2026|GUARANTEED
Name five fundamental characteristics shared by all living organism. - ANSWER 1. Cells
2. Energy consumption
3. Information
4. Replication
5. Evolutionary adaptation
Describe the two components of cell theory. - ANSWER 1. All living things are made up
of cell or cells.
2. Cells come from other cells.
Define energy, and describe the major forms it can take. Understand in what way chemical
bonds can be considered a form of energy. - ANSWER Energy is the capacity to do
work or to supply heat. Potential energy- may be stored. Kinetic energy- may be available in
the form of motion. When chemical bonds are formed, energy is released. The internal
energy of the system goes down
Explain, both in mathematical terms and in plain English, how changes in entropy and
potential energy determine whether or not a reaction is spontaneous. Understand under
what conditions a nonspontaneous reaction can occur. - ANSWER ΔG(ibbs free energy)
= ΔH (enthalpy) - T ΔS (entropy)
If ΔG is negative (big loss of potential energy, and/or big gain of disorder): the reaction is
Exergonic (Exit of energy). SPONTANEOUS
1
,If ΔG is positive (big gain of potential energy, and/or big loss of disorder): the reaction is
Endergonic (Input of energy). NOT SPONTANEOUS
Explain and give examples of why proteins are essential to cell function. - ANSWER -
Enzyme Catalysis (chemistry)
-Cell receptors (signalling and immune response)
-Transport (food uptake, e.g.)
-Support (cell/organism structure)
-Motion (muscles, flagella)
-Regulation (gene expression)
Sketch the basic structure of an amino acid, and describe why and how the side chains affect
the function and structure of each amino acid. - ANSWER Structure: Central carbon
atom bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom and in
the 4th position, a side group (R-Group). The side chain is the chemical identity to the amino
acid and extends out from the backbone, making it possible for them to interact with each
other and with water. (Visual representation: slide 4)
Sketch a nucleotide, label its three basic parts, and identify the 2', 3', and 5' carbons. -
ANSWER A nucleotide has a sugar or deoxyribose group, a phosphate that is attached
on the 5' carbon and an organic nitrogenous base which is attached to the 3' carbon. Ribose
has an -OH on the 2' carbon, Deoxyribose has a H' on the 2' carbon.
Describe the primary, secondary, tertiary, and quaternary structures of RNA, and explain in
what ways RNA differs from DNA. - ANSWER RNA's primary structure consists of a
sequence of nitrogen-containing bases that contain information in the form of a molecular
code. Its secondary structure includes short double helixes and structures called hairpins
that holds RNA strands together. Its tertiary and quaternary structures that fold secondary
structures into complex shapes or hold different RNA strands together. RNA has Uracil
instead of Thymine, it is single stranded, its ribose has an extra -OH group, and it acts as a
transcript of DNA expression. Also, DNA does not have a tertiary and quaternary structure.
2
,Explain why and how the secondary structure of DNA allows organisms to store and copy
information. - ANSWER Complementary base pairing allows each strand of a DNA
molecule to be copied exactly, producing two daughter molecules. DNA's primary structure
serves as a mold or template for the synthesis of a complementary strand and DNA contains
the information required for a copy of itself to be made
Explain why RNA, and not DNA, was probably the first self-replicating molecule, and describe
at least one piece of experimental evidence that supports this hypothesis. -
ANSWER To make a copy of itself, the first living organism had to provide a template
that could be copied and catalyze polymerization reactions that would link monomers into a
copy of that template. RNA is capable of both.
One experimental evidence is by Wendy Johnston and David Bartel. They found that
ribozymes isolated in each round are copied, the molecules that result are not identical in
terms of their primary sequence because mutations were introduced during the copying
step. By isolating the best enzyme and copying them in the next round, they continually
selected ribozymes that were more efficient. This was to mimic the process of natural
selection
List the features shared by all carbohydrates. - ANSWER A molecule made up of a
bunch of carbon, hydrogen, and oxygen. These atoms are arranged in a few specific ways:
they have a carbon atom that's bonded to a carbonyl group (>C=O), several hydroxyl
functional groups (-OH), and many C-H bonds.
Sketch several representative monosaccharides, illustrating three ways in which
monosaccharides can differ from one another. - ANSWER Monosaccharide have a
carbonyl group at various locations , several hydroxyl functional groups at various locations,
and many carbon-hydrogen (C-H) bonds (energy). Linear form, ring form, alpha vs beta form.
Give examples of the four major functions that carbohydrates can perform in cells (raw
materials, structure, cell identity, and chemical energy storage). - ANSWER Raw
materials: Sugars frequently furnish the raw "carbon skeletons" that are used as a building
blocks in the synthesis of important molecules. Amino acids use sugars as a starting point.
3
, Structure: Cellulose and chitin, along with modified polysaccharide peptidoglycan, are key to
structural compounds. They form fibers that give cells and organisms strength and elasticity.
Cell identity: Enormous number of structurally distinct monosaccharides make it possible for
an enormous number of unique oligosaccharides to exist. As a result, each cell type and
each species can display a unique identity
Chemical energy storage: Kinetic energy in sunlight is converted to chemical energy stored in
bonds of carbohydrates by photosynthesis.
Sketch a phospholipid's molecular structure, and explain why phospholipids spontaneously
form bilayers in water. - ANSWER Phospholipids have polar ends and nonpolar tails.
The hydrophobic tails on the phospholipid molecules react with one another, and are
repelled by water. The polar head groups on the phospholipids are hydrophilic and react
with water. For these reasons, the phospholipids organize themselves in such a way as to
maximize the hydrophobic and hydrophilic interactions. The form that accomplishes this the
best is a bilayer.
Predict which way a certain substance will diffuse, given its concentration on either side of a
selectively permeable membrane. - ANSWER If a solution is hypertonic (the solution
surrounding the cell has higher concentration of solutes) water will rush out of the cell,
shrinking it. If a solution is hypotonic, (the solution surrounding the cell has less
concentration of solutes) water will rush into the cell, enlarging it. If a solution is isotonic,
(the concentration of solute is the same inside and outside the cell) the water stays as is.
Describe at least three ways in which membrane proteins can help substances cross a cell
membrane. - ANSWER 1. Carrier proteins are in the phospholipid bilayer (the
membrane) and they transport large molecules: glucose and amino acids via the proteins by
changing the shape of them to make them more easy to transport.
2. Channel proteins: Used for ions (as the membrane is polar and so cannot transport
charged particles), and they can be gated and so selected about what they allow through the
protein.
4
UPDATE!!!2025/2026|GUARANTEED
Name five fundamental characteristics shared by all living organism. - ANSWER 1. Cells
2. Energy consumption
3. Information
4. Replication
5. Evolutionary adaptation
Describe the two components of cell theory. - ANSWER 1. All living things are made up
of cell or cells.
2. Cells come from other cells.
Define energy, and describe the major forms it can take. Understand in what way chemical
bonds can be considered a form of energy. - ANSWER Energy is the capacity to do
work or to supply heat. Potential energy- may be stored. Kinetic energy- may be available in
the form of motion. When chemical bonds are formed, energy is released. The internal
energy of the system goes down
Explain, both in mathematical terms and in plain English, how changes in entropy and
potential energy determine whether or not a reaction is spontaneous. Understand under
what conditions a nonspontaneous reaction can occur. - ANSWER ΔG(ibbs free energy)
= ΔH (enthalpy) - T ΔS (entropy)
If ΔG is negative (big loss of potential energy, and/or big gain of disorder): the reaction is
Exergonic (Exit of energy). SPONTANEOUS
1
,If ΔG is positive (big gain of potential energy, and/or big loss of disorder): the reaction is
Endergonic (Input of energy). NOT SPONTANEOUS
Explain and give examples of why proteins are essential to cell function. - ANSWER -
Enzyme Catalysis (chemistry)
-Cell receptors (signalling and immune response)
-Transport (food uptake, e.g.)
-Support (cell/organism structure)
-Motion (muscles, flagella)
-Regulation (gene expression)
Sketch the basic structure of an amino acid, and describe why and how the side chains affect
the function and structure of each amino acid. - ANSWER Structure: Central carbon
atom bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom and in
the 4th position, a side group (R-Group). The side chain is the chemical identity to the amino
acid and extends out from the backbone, making it possible for them to interact with each
other and with water. (Visual representation: slide 4)
Sketch a nucleotide, label its three basic parts, and identify the 2', 3', and 5' carbons. -
ANSWER A nucleotide has a sugar or deoxyribose group, a phosphate that is attached
on the 5' carbon and an organic nitrogenous base which is attached to the 3' carbon. Ribose
has an -OH on the 2' carbon, Deoxyribose has a H' on the 2' carbon.
Describe the primary, secondary, tertiary, and quaternary structures of RNA, and explain in
what ways RNA differs from DNA. - ANSWER RNA's primary structure consists of a
sequence of nitrogen-containing bases that contain information in the form of a molecular
code. Its secondary structure includes short double helixes and structures called hairpins
that holds RNA strands together. Its tertiary and quaternary structures that fold secondary
structures into complex shapes or hold different RNA strands together. RNA has Uracil
instead of Thymine, it is single stranded, its ribose has an extra -OH group, and it acts as a
transcript of DNA expression. Also, DNA does not have a tertiary and quaternary structure.
2
,Explain why and how the secondary structure of DNA allows organisms to store and copy
information. - ANSWER Complementary base pairing allows each strand of a DNA
molecule to be copied exactly, producing two daughter molecules. DNA's primary structure
serves as a mold or template for the synthesis of a complementary strand and DNA contains
the information required for a copy of itself to be made
Explain why RNA, and not DNA, was probably the first self-replicating molecule, and describe
at least one piece of experimental evidence that supports this hypothesis. -
ANSWER To make a copy of itself, the first living organism had to provide a template
that could be copied and catalyze polymerization reactions that would link monomers into a
copy of that template. RNA is capable of both.
One experimental evidence is by Wendy Johnston and David Bartel. They found that
ribozymes isolated in each round are copied, the molecules that result are not identical in
terms of their primary sequence because mutations were introduced during the copying
step. By isolating the best enzyme and copying them in the next round, they continually
selected ribozymes that were more efficient. This was to mimic the process of natural
selection
List the features shared by all carbohydrates. - ANSWER A molecule made up of a
bunch of carbon, hydrogen, and oxygen. These atoms are arranged in a few specific ways:
they have a carbon atom that's bonded to a carbonyl group (>C=O), several hydroxyl
functional groups (-OH), and many C-H bonds.
Sketch several representative monosaccharides, illustrating three ways in which
monosaccharides can differ from one another. - ANSWER Monosaccharide have a
carbonyl group at various locations , several hydroxyl functional groups at various locations,
and many carbon-hydrogen (C-H) bonds (energy). Linear form, ring form, alpha vs beta form.
Give examples of the four major functions that carbohydrates can perform in cells (raw
materials, structure, cell identity, and chemical energy storage). - ANSWER Raw
materials: Sugars frequently furnish the raw "carbon skeletons" that are used as a building
blocks in the synthesis of important molecules. Amino acids use sugars as a starting point.
3
, Structure: Cellulose and chitin, along with modified polysaccharide peptidoglycan, are key to
structural compounds. They form fibers that give cells and organisms strength and elasticity.
Cell identity: Enormous number of structurally distinct monosaccharides make it possible for
an enormous number of unique oligosaccharides to exist. As a result, each cell type and
each species can display a unique identity
Chemical energy storage: Kinetic energy in sunlight is converted to chemical energy stored in
bonds of carbohydrates by photosynthesis.
Sketch a phospholipid's molecular structure, and explain why phospholipids spontaneously
form bilayers in water. - ANSWER Phospholipids have polar ends and nonpolar tails.
The hydrophobic tails on the phospholipid molecules react with one another, and are
repelled by water. The polar head groups on the phospholipids are hydrophilic and react
with water. For these reasons, the phospholipids organize themselves in such a way as to
maximize the hydrophobic and hydrophilic interactions. The form that accomplishes this the
best is a bilayer.
Predict which way a certain substance will diffuse, given its concentration on either side of a
selectively permeable membrane. - ANSWER If a solution is hypertonic (the solution
surrounding the cell has higher concentration of solutes) water will rush out of the cell,
shrinking it. If a solution is hypotonic, (the solution surrounding the cell has less
concentration of solutes) water will rush into the cell, enlarging it. If a solution is isotonic,
(the concentration of solute is the same inside and outside the cell) the water stays as is.
Describe at least three ways in which membrane proteins can help substances cross a cell
membrane. - ANSWER 1. Carrier proteins are in the phospholipid bilayer (the
membrane) and they transport large molecules: glucose and amino acids via the proteins by
changing the shape of them to make them more easy to transport.
2. Channel proteins: Used for ions (as the membrane is polar and so cannot transport
charged particles), and they can be gated and so selected about what they allow through the
protein.
4
