1.
Plant cells have one big____ used for storage, but animal cells have lots of small ones.
Correct Answer
C. Vacuole
Explanation
Plant cells have one big vacuole used for storage, but animal cells have lots of small ones. The vacuole in plant cells is a large membrane-bound organelle that stores water, nutrients, and waste products. It helps maintain turgor pressure, which is important for cell structure and support. In animal cells, vacuoles are smaller and more numerous, and they serve various functions such as storing waste, maintaining ion balance, and regulating cell volume. Therefore, the presence of one big vacuole in plant cells and multiple small vacuoles in animal cells is a key difference between the two cell types.
2.
Which description best fits the cell membrane?
Correct Answer
D. Semi-permeable
Explanation
The cell membrane is described as semi-permeable because it allows certain substances to pass through while restricting the passage of others. This selective permeability is essential for maintaining the internal environment of the cell and regulating the movement of molecules in and out of the cell. It ensures that necessary nutrients and molecules can enter the cell, while waste products and harmful substances are kept out.
3.
Having many ribosomes attached to it, this organelle produces proteins as well as other substances and then transports them to other parts of the cell
Correct Answer
A. Rough ER
Explanation
The rough endoplasmic reticulum (ER) is the correct answer. It is called "rough" because it has many ribosomes attached to its surface. These ribosomes help in the production of proteins. The rough ER is responsible for synthesizing and modifying proteins, as well as transporting them to other parts of the cell. It plays a crucial role in protein synthesis and secretion. The smooth ER, on the other hand, is involved in lipid synthesis and detoxification. The nucleolus is a substructure within the nucleus that is responsible for producing ribosomes.
4.
"Fluid mosaic model" is a term used to describe the
Correct Answer
C. Plasma membrane
Explanation
The term "Fluid mosaic model" is used to describe the plasma membrane. This model suggests that the plasma membrane is composed of a fluid phospholipid bilayer with embedded proteins that are able to move laterally within the membrane. The fluidity of the membrane allows for flexibility and the ability to accommodate various cellular processes such as endocytosis and cell signaling. The mosaic aspect refers to the diverse array of proteins and lipids that make up the membrane, each with their own specific functions and roles.
5.
These openings in the nuclear envelope allow substances to enter and leave the nucleus
Correct Answer
B. Nuclear pores
Explanation
Nuclear pores are openings in the nuclear envelope that allow substances to enter and leave the nucleus. These pores are made up of proteins and act as gateways, regulating the passage of molecules such as RNA and proteins between the nucleus and the cytoplasm. The integral proteins are embedded in the nuclear envelope and form the structure of the nuclear pores, while the peripheral proteins are located on the surface of the nuclear envelope and assist in the transport process. Therefore, the correct answer is nuclear pores.
6.
This structure, not found in animal cells, provides strength for plant cells and is found outside the plasma membrane
Correct Answer
C. Cell wall
Explanation
The cell wall is a structure that is unique to plant cells and provides strength and support. It is located outside the plasma membrane and helps maintain the shape of the cell. Animal cells do not have a cell wall, which is why this structure is not found in them. The central vacuole and plastids are also found in plant cells, but they do not provide strength for the cell like the cell wall does.
7.
The process by which substances pass through the cell membrane without expending energy is called:
Correct Answer
B. Passive transport
Explanation
Passive transport refers to the process by which substances pass through the cell membrane without the need for energy expenditure. Unlike active transport, which requires energy, passive transport occurs through simple diffusion or facilitated diffusion. In simple diffusion, molecules move from an area of higher concentration to an area of lower concentration, while facilitated diffusion involves the assistance of transport proteins to move molecules across the membrane. Both processes do not require the cell to expend energy.
8.
The process by which substances move from regions of high concentration to regions of low concentration is called:
Correct Answer
B. Diffusion
Explanation
Diffusion is the process by which substances move from regions of high concentration to regions of low concentration. It occurs due to the random motion of particles, where they spread out and mix with each other. This movement is driven by the concentration gradient, which is the difference in concentration between two regions. Unlike active transport, which requires energy, diffusion is a passive process and does not require any external energy source. Phagocytosis and endocytosis involve the engulfment of particles by cells and are not related to the movement of substances based on concentration gradient.
9.
The movement of water through a selectively peremeable membrane is known as:
Correct Answer
B. Osmosis
Explanation
Osmosis is the movement of water through a selectively permeable membrane. In osmosis, water molecules move from an area of lower solute concentration to an area of higher solute concentration, in order to equalize the concentration on both sides of the membrane. This process does not require any energy input and is driven by the concentration gradient. Facilitated diffusion involves the movement of molecules across a membrane with the help of transport proteins, diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration, and active transport requires energy to move molecules against their concentration gradient.
10.
The site where ribosomes are assembled is the:
Correct Answer
D. Nucleolus
Explanation
The nucleolus is the correct answer because it is the site within the nucleus where ribosomes are assembled. It contains the necessary components for ribosome synthesis, such as ribosomal RNA (rRNA) and proteins. The nucleolus plays a crucial role in the production of ribosomes, which are responsible for protein synthesis in the cell.
11.
Because bacteria do not contain nuclei, they are known as:
Correct Answer
A. Prokaryotes
Explanation
Bacteria are known as prokaryotes because they lack a nucleus. Prokaryotes are single-celled organisms that do not have a membrane-bound nucleus or other membrane-bound organelles. Instead, their genetic material is found in a region called the nucleoid. This distinguishes them from eukaryotes, which have a true nucleus surrounded by a nuclear membrane. Phagocytes are a type of immune cell that can engulf and destroy pathogens, while endocytes is not a recognized term in biology.
12.
Which structure would a cell that is active in protein synthesis contain?
Correct Answer
D. Ribosomes
Explanation
Ribosomes are the correct answer because they are the cellular structures responsible for protein synthesis. They are found in both prokaryotic and eukaryotic cells and can be free-floating in the cytoplasm or attached to the endoplasmic reticulum. Ribosomes read the genetic information from mRNA and use it to assemble amino acids into proteins. Therefore, a cell that is actively involved in protein synthesis would contain ribosomes.
13.
Which structures would be found in a maple tree cell but not a human cell?
Correct Answer
B. Chloroplasts and cell walls
Explanation
Chloroplasts are only found in plant cells, specifically in the cells of photosynthetic organisms like maple trees. These structures are responsible for carrying out photosynthesis, the process by which plants convert sunlight into energy. Human cells do not have chloroplasts since humans are not capable of photosynthesis. Cell walls are also unique to plant cells and provide support and protection to the cell. In contrast, human cells do not have cell walls, but instead have a flexible cell membrane that regulates the movement of substances in and out of the cell.
14.
Which plant organelle stores water?
Correct Answer
D. Vacuole
Explanation
The correct answer is vacuole. Vacuoles are plant organelles that store water, along with other substances such as ions, nutrients, and waste products. They are large, fluid-filled sacs found in the cytoplasm of plant cells. Vacuoles help maintain turgor pressure, which gives rigidity to the plant cell and helps it maintain its shape. Additionally, vacuoles play a role in regulating the concentration of ions and other molecules within the cell, as well as storing pigments and toxins.
15.
Water has an important stabilizing effect on temperature in living organisms and their environments because as water absorbs heat, much of the energy is used to ____________ instead of raising the temperature.
Correct Answer
D. Break hydrogen bonds
Explanation
Water has a high specific heat capacity, meaning it can absorb a large amount of heat energy before its temperature increases significantly. When water absorbs heat, the energy is used to break the hydrogen bonds between water molecules rather than increasing the temperature. This stabilizes the temperature in living organisms and their environments because it prevents rapid fluctuations in temperature.
16.
Reactions that use the equivalent of a water molecule to break a molecule into smaller subunits are called
Correct Answer
C. Hydrolysis reactions
Explanation
Hydrolysis reactions involve the breaking of a molecule into smaller subunits by the addition of a water molecule. This process occurs when a water molecule is split into a hydrogen ion (H+) and a hydroxide ion (OH-), and these ions are used to break the bonds within the molecule. Therefore, hydrolysis reactions are the correct answer for this question. Equilibrium reactions involve reversible reactions that reach a state of balance, hydration reactions involve the addition of water molecules to a substance, redox reactions involve the transfer of electrons, and dehydration synthesis reactions involve the removal of a water molecule to form a larger molecule.
17.
Which of these terms is most inclusive?
Correct Answer
E. Carbohydrate
Explanation
Carbohydrate is the most inclusive term among the given options. It encompasses all the other terms mentioned in the question. A carbohydrate is a biomolecule consisting of carbon, hydrogen, and oxygen atoms, and it can be classified into different types such as monosaccharides, disaccharides, starch, and polysaccharides. Therefore, carbohydrate includes all these terms within its broader category.
18.
Which functional group is polar, consists of oxygen and hydrogen, and is a key component of alcohols?
Correct Answer
B. Hydroxyl
Explanation
The hydroxyl functional group is polar because it consists of oxygen and hydrogen. It is a key component of alcohols, which are organic compounds that contain one or more hydroxyl groups attached to a carbon atom. The presence of the hydroxyl group in alcohols allows them to participate in hydrogen bonding and exhibit various chemical properties such as solubility in water and reactivity with other compounds.
19.
Which functional group is found in all proteins?
Correct Answer
D. Amino
Explanation
The functional group found in all proteins is the amino group. This group consists of a nitrogen atom bonded to two hydrogen atoms, and it is responsible for the formation of peptide bonds between amino acids, which are the building blocks of proteins. The amino group also plays a crucial role in the overall structure and function of proteins.
20.
Which functional group is responsible for the coiled shape of DNA?
Correct Answer
C. pHospHate
Explanation
The phosphate functional group is responsible for the coiled shape of DNA. Phosphate groups form the backbone of the DNA molecule, connecting the sugar molecules together. The negatively charged phosphate groups repel each other, causing the DNA molecule to twist and coil into a double helix structure. This coiled shape is essential for the stability and function of DNA in storing and transmitting genetic information.
21.
What kinds of reactions remove the equivalent of a water molecule when subunits are joined to make a larger molecule?
Correct Answer
E. Dehydration synthesis reactions
Explanation
Dehydration synthesis reactions remove the equivalent of a water molecule when subunits are joined to make a larger molecule. In this type of reaction, a hydroxyl group (-OH) from one subunit and a hydrogen atom (-H) from another subunit are removed, resulting in the formation of a covalent bond between the two subunits and the release of a water molecule. This process is essential in the formation of complex molecules such as carbohydrates, proteins, and nucleic acids.
22.
Although they have a diversity of structures, all members of this group of organic molecules are primarily nonpolar and thus water-insoluble.
Correct Answer
B. Lipids
Explanation
Lipids are a diverse group of organic molecules that are primarily nonpolar and water-insoluble. This is due to their hydrophobic nature, meaning they repel water. Lipids include fats, oils, waxes, and steroids, and they serve various functions in living organisms such as energy storage, insulation, and protection. Their nonpolar nature makes them ideal for these roles as they can form barriers and provide structural support.
23.
What organic molecules have a chemical formula that is (or is very nearly) a multiple of 1 Carbon atom to 1 Water molecule?
Correct Answer
D. Carbohydrates
Explanation
Carbohydrates have a chemical formula that is a multiple of 1 carbon atom to 1 water molecule. This is because the basic unit of carbohydrates, called monosaccharides, have the formula (CH2O)n, where n is the number of carbon atoms. This formula represents a ratio of 1 carbon atom to 1 water molecule (H2O), making carbohydrates the correct answer. Proteins, lipids, nucleic acids, and amino acids do not have this specific ratio in their chemical formulas.
24.
What kind of molecules are monosaccharides and disaccharides?
Correct Answer
D. Carbohydrates
Explanation
Monosaccharides and disaccharides are types of molecules that belong to the carbohydrate group. Carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen atoms. Monosaccharides are simple sugars that cannot be further hydrolyzed, while disaccharides consist of two monosaccharide units joined together by a glycosidic bond. Both monosaccharides and disaccharides are important sources of energy for living organisms.
25.
Which group of organic molecules are held together with peptide bonds?
Correct Answer
A. Proteins
Explanation
Proteins are the group of organic molecules that are held together with peptide bonds. Peptide bonds are formed between amino acids, which are the building blocks of proteins. These bonds create a chain-like structure, forming the primary structure of a protein. Therefore, proteins are the correct answer to the question.
26.
Probably the most abundant carbohydrate on Earth, this unbranched chain of B-glucose subunits is the primary structural molecule in plant cell walls.
Correct Answer
C. Cellulose
Explanation
Cellulose is the correct answer because it is an unbranched chain of B-glucose subunits and is the primary structural molecule in plant cell walls. It is also mentioned that cellulose is probably the most abundant carbohydrate on Earth, further supporting its selection as the correct answer.
27.
In many animals this polysaccharide is found in large quantities in liver and muscle cells. It is highly branched.
Correct Answer
D. Glycogen
Explanation
Glycogen is a polysaccharide that is found in large quantities in liver and muscle cells of many animals. It is highly branched, meaning it has many side chains. Glycogen serves as a storage form of glucose and can be quickly broken down into glucose when energy is needed. It plays a crucial role in maintaining blood sugar levels and providing energy during periods of fasting or intense physical activity.
28.
An amphipathic molecule, such as a soap or detergent, has
Correct Answer
C. A hydropHobic and a hydropHilic portion
Explanation
An amphipathic molecule, such as a soap or detergent, has both a hydrophobic and a hydrophilic portion. This means that one part of the molecule is attracted to water (hydrophilic) while the other part repels water (hydrophobic). This dual nature allows amphipathic molecules to interact with both water and non-polar substances, making them effective at dissolving oils and dirt in water-based solutions.
29.
In which of the following reactions must the equivalent of a water molecule be added in order to break a bond?
Correct Answer
C. Glycogen = glucose
Explanation
In the reaction glycogen = glucose, the equivalent of a water molecule must be added in order to break a bond. This is because glycogen is a polysaccharide made up of multiple glucose molecules bonded together. To break these bonds and convert glycogen into glucose, a water molecule needs to be added through a hydrolysis reaction. This hydrolysis reaction breaks the glycosidic bonds between the glucose molecules, resulting in the release of individual glucose units.
30.
Which of these are the main structural components of biological membranes?
Correct Answer
D. pHospHolipids
Explanation
Phospholipids are the main structural components of biological membranes. They are composed of a hydrophilic head and hydrophobic tails, which allow them to form a bilayer arrangement in water-based environments. This arrangement creates a barrier that separates the interior of cells and organelles from the external environment. Starches, triglycerides, proteins, and steroids are not the main structural components of biological membranes. Starches are polysaccharides used for energy storage, triglycerides are fats used for energy storage, proteins have various functions within cells, and steroids are involved in signaling and regulation processes.
31.
Which of the following is NOT a major function of proteins in living organisms?
Correct Answer
E. Storing genetic information
Explanation
Proteins are macromolecules that perform various functions in living organisms. They are involved in speeding up biological reactions, transporting substances across membranes, providing structural support, and regulating the activity of other cellular molecules. However, storing genetic information is not a major function of proteins. Genetic information is stored in the form of DNA molecules, which are made up of nucleotides, not proteins. Proteins are responsible for carrying out the instructions encoded in DNA, but they do not store the genetic information themselves.
32.
Proteins are polymers of
Correct Answer
A. Amino acids
Explanation
Proteins are composed of amino acids. Amino acids are the building blocks of proteins, which are joined together by peptide bonds to form long chains. These chains then fold into specific three-dimensional structures, allowing proteins to carry out their various functions in the body. Therefore, the correct answer is amino acids.
33.
What structure is defined as the sequence of amino acids in a protein?
Correct Answer
A. Primary
Explanation
The structure defined as the sequence of amino acids in a protein is called the primary structure. This refers to the specific order in which the amino acids are linked together to form the protein chain. The primary structure is crucial as it determines the overall shape and function of the protein. Any alterations or mutations in the sequence can have significant effects on the protein's structure and function.
34.
The structure of a protein that refers to the conformation, or overall three-dimensional shape, of a polypeptide that has been folded into a functional protein...
Correct Answer
C. Tertiary
Explanation
The correct answer is tertiary. The tertiary structure of a protein refers to its overall three-dimensional shape, which is formed when the polypeptide chain is folded into a functional protein. This folding is driven by various interactions between the amino acid residues, such as hydrogen bonding, disulfide bridges, hydrophobic interactions, and electrostatic interactions. The tertiary structure is crucial for the protein's function, as it determines its specific shape and allows it to interact with other molecules in the cell.
35.
Which structure of a protein is determined between the amino acids side groups from two different polypeptide chains?
Correct Answer
D. Quaternary
Explanation
The quaternary structure of a protein is determined by the interactions between the amino acid side groups from two or more different polypeptide chains. This structure refers to the arrangement and organization of multiple polypeptide chains in a protein complex. It is responsible for the overall shape and function of the protein complex. The primary structure refers to the sequence of amino acids in a single polypeptide chain, the secondary structure refers to the local folding patterns such as alpha helices and beta sheets, and the tertiary structure refers to the overall 3D folding of a single polypeptide chain. The globular structure refers to a compact and rounded shape often associated with functional proteins.
36.
Excessive heat or extremes of pH often cause denaturation of proteins, which means that the proteins.
Correct Answer
D. Are no longer in a functional three dimensional structure.
Explanation
Excessive heat or extremes of pH can disrupt the weak bonds that maintain the specific shape of a protein. When these bonds break, the protein loses its functional three-dimensional structure, which is essential for its proper functioning. Without the correct shape, the protein may not be able to interact with other molecules or perform its intended biological functions. Therefore, the correct answer is that the proteins are no longer in a functional three-dimensional structure.
37.
Inside a cell, the cytoplasm consists of a .4 M concentration. If dropped into a beaker containing .25 M solution, the cell would be....
Correct Answer
B. Hypertonic
Explanation
The cell would be hypertonic because the cytoplasm has a higher concentration (0.4 M) compared to the solution in the beaker (0.25 M). In a hypertonic solution, there is a higher solute concentration outside the cell, causing water to move out of the cell through osmosis, leading to cell shrinkage.
38.
Inside a cell, the cytoplasm consists of a .4 M concentration. If dropped into a beaker containing .25 M solution, the cell would....
Correct Answer
A. Swell
Explanation
When a cell with a higher concentration of cytoplasm (.4 M) is dropped into a beaker with a lower concentration (.25 M), water molecules will move from the beaker into the cell through the process of osmosis. This is because water moves from an area of lower solute concentration (the beaker) to an area of higher solute concentration (the cell). As a result, the cell will gain water and increase in size, causing it to swell.
39.
Osmosis is...
Correct Answer
D. Type of diffusion, and passive transport.
Explanation
Osmosis is a type of diffusion, where the movement of water molecules occurs from an area of higher concentration to an area of lower concentration across a selectively permeable membrane. It is considered a passive transport process because it does not require the input of energy.
40.
The molecule is able to move into a cell due to facilitated diffusion.
Correct Answer
D. Glucose
Explanation
Glucose is able to move into a cell through facilitated diffusion because it is a polar molecule and cannot easily pass through the hydrophobic lipid bilayer of the cell membrane. Facilitated diffusion involves the use of specific protein channels or carrier proteins that allow the movement of polar molecules like glucose across the membrane, down their concentration gradient, without the need for energy input. This process ensures that glucose can be transported into the cell efficiently, as it is an important source of energy for cellular processes.