Chemistry of Life
What are the four types of macromolecules essential for life?
A) Carbohydrates, Proteins, Nucleic acids, and Lipids
B) Proteins, Fats, Water, and Vitamins
C) Nucleic acids, Carbohydrates, Sugars, and Enzymes
D) Lipids, Enzymes, Proteins, and Water
A) Carbohydrates, Proteins, Nucleic acids, and Lipids
Which of the following is an example of a biotic factor in an environment?
A) Temperature
B) Water availability
C) Plants
D) Soil type
C) Plants
What does 'selective permeability' refer to in the context of a cell membrane?
A) The ability of the cell membrane to allow all substances to pass freely
B) The ability of the cell membrane to regulate what enters and exits the cell
C) The ability of the cell membrane to prevent any substances from entering the cell
D) The process by which the cell membrane produces energy
B) The ability of the cell membrane to regulate what enters and exits the cell
How do cancer cells "beat the system"?
A) They grow and divide uncontrollably, bypassing normal cell cycle checkpoints.
B) They stop dividing once they reach a certain size.
C) They only divide when the body needs more cells.
D) They cannot undergo apoptosis (cell death) when damaged.
A) They grow and divide uncontrollably, bypassing normal cell cycle checkpoints.
Which of the following correctly describes the base pairing in DNA?
A) Adenine pairs with Cytosine, and Guanine pairs with Thymine
B) Adenine pairs with Guanine, and Thymine pairs with Cytosine
C) Adenine pairs with Thymine, and Guanine pairs with Cytosine
D) Cytosine pairs with Thymine, and Adenine pairs with Guanine
C) Adenine pairs with Thymine, and Guanine pairs with Cytosine
Explain how water’s properties, like cohesion and high heat capacity, impact life on Earth.
A) Water helps organisms move faster in aquatic environments.
B) Water allows plants to absorb sunlight and grow faster.
C) Water makes it easier for organisms to breathe in dry environments.
D) Water helps regulate temperature and allows for the transportation of nutrients.
D) Water helps regulate temperature and allows for the transportation of nutrients.
Which of the following organisms is considered a secondary consumer in an ecosystem?
A) Fox
B) Deer
C) Grass
D) Mushroom
A) Fox
Which of the following materials can easily cross a cell membrane due to its selective permeability?
A) Large proteins
B) Ions
C) Small nonpolar molecules (e.g., oxygen, carbon dioxide)
D) Glucose molecules
C) Small nonpolar molecules (e.g., oxygen, carbon dioxide)
Which of the following correctly defines a haploid cell?
A) A cell with two sets of chromosomes, one from each parent
B) A cell with one set of chromosomes, half the number found in diploid cells
C) A cell with no chromosomes
D) A cell that has undergone mitosis
B) A cell with one set of chromosomes, half the number found in diploid cells
What is a key structural difference between DNA and RNA?
A) DNA is double-stranded, while RNA is single-stranded
B) RNA contains thymine, while DNA contains uracil
C) DNA has a ribose sugar, while RNA has a deoxyribose sugar
D) RNA is only found in the nucleus, while DNA is found only in the cytoplasm
A) DNA is double-stranded, while RNA is single-stranded
What is the key difference between saturated and unsaturated fats, and how does this affect their function in living organisms?
A) Saturated fats have no double bonds and are solid at room temperature, while unsaturated fats have double bonds and are liquid.
B) Saturated fats have double bonds and are liquid, while unsaturated fats have no double bonds and are solid at room temperature.
C) Saturated fats are easier for the body to digest, while unsaturated fats cause weight gain.
D) Saturated fats contain more oxygen than unsaturated fats.
A) Saturated fats have no double bonds and are solid at room temperature, while unsaturated fats have double bonds and are liquid.
How do energy and nutrients flow in an ecosystem?
A) Energy flows in a cycle, while nutrients flow in a straight line.
B) Energy flows through the food chain in one direction, while nutrients cycle between producers, consumers, and decomposers.
C) Energy and nutrients both flow in a straight line from producers to tertiary consumers.
D) Energy is recycled in the ecosystem, while nutrients are lost to the atmosphere.
B) Energy flows through the food chain in one direction, while nutrients cycle between producers, consumers, and decomposers.
Which of the following is true about diffusion and osmosis?
A) Both diffusion and osmosis require energy from the cell.
B) Diffusion involves the movement of water molecules, while osmosis involves the movement of solutes.
C) Diffusion involves the movement of solutes from high to low concentration, while osmosis specifically refers to the movement of water across a membrane.
D) Diffusion and osmosis only occur in plant cells.
C) Diffusion involves the movement of solutes from high to low concentration, while osmosis specifically refers to the movement of water across a membrane.
What happens to a diploid cell (2n) undergoing mitosis?
A) It divides into one haploid cell
B) It divides into four diploid cells
C) It divides into two haploid cells
D) It divides into two diploid cells
D) It divides into two diploid cells
Which of the following correctly describes the central dogma of molecular biology?
A) DNA → RNA → Protein
B) Protein → RNA → DNA
C) RNA → Protein → DNA
D) DNA → Protein → RNA
A) DNA → RNA → Protein
Describe the roles of proteins in living organisms. Provide at least three examples of functions that proteins perform in the body.
A) Proteins act as enzymes, provide energy, and store genetic information.
B) Proteins are used for structural support, catalyzing reactions, and transporting molecules.
C) Proteins store fat, help in photosynthesis, and act as hormones.
D) Proteins store water, digest food, and produce carbohydrates.
B) Proteins are used for structural support, catalyzing reactions, and transporting molecules.
Which of the following accurately describes the role of decomposers in an ecosystem?
A) Decomposers break down dead organisms, releasing nutrients back into the soil for use by producers.
B) Decomposers consume producers and secondary consumers.
C) Decomposers are responsible for capturing sunlight and converting it into energy.
D) Decomposers are only found at the top of the food chain.
A) Decomposers break down dead organisms, releasing nutrients back into the soil for use by producers.
Which of the following processes is an example of active transport, requiring energy to move substances across the cell membrane?
A) Endocytosis
B) Osmosis
C) Diffusion
D) Facilitated diffusion
A) Endocytosis
Which of the following is true about meiosis and the cells it produces?
A) Meiosis results in two diploid cells, each genetically identical to the parent.
B) Meiosis results in four haploid cells, each genetically unique.
C) Meiosis results in two haploid cells, each genetically identical to the parent.
D) Meiosis produces no new cells, only genetic material.
B) Meiosis results in four haploid cells, each genetically unique.
During transcription, what happens to the DNA?
A) The DNA is replicated to form a new copy.
B) The DNA is broken down into nucleotides.
C) The DNA is translated into a protein.
D) The DNA is split into two strands, and mRNA is synthesized from one of them.
D) The DNA is split into two strands, and mRNA is synthesized from one of them.
Why is water considered a universal solvent, and how does this property contribute to biochemical reactions necessary for life?
A) Water dissolves a wide range of non-polar substances, allowing cells to store energy efficiently.
B) Water dissolves polar substances, helping to transport ions and molecules in and out of cells, facilitating chemical reactions.
C) Water dissolves only proteins, which is necessary for enzyme activity.
D) Water dissolves gases like oxygen, which helps organisms breathe underwater.
B) Water dissolves polar substances, helping to transport ions and molecules in and out of cells, facilitating chemical reactions.
What does the term 'trophic level' refer to in an ecosystem?
A) The level at which energy is lost in an ecosystem
B) The total number of producers in an ecosystem
C) The level at which photosynthesis occurs in an ecosystem
D) The position an organism occupies in a food chain, based on its source of energy
D) The position an organism occupies in a food chain, based on its source of energy
How do endocytosis and exocytosis differ in their role in the cell?
A) Endocytosis moves substances out of the cell, while exocytosis moves substances into the cell.
B) Endocytosis involves engulfing materials into the cell, while exocytosis involves expelling materials out of the cell.
C) Endocytosis and exocytosis both occur in the nucleus, while diffusion occurs at the cell membrane.
D) Endocytosis is an example of passive transport, while exocytosis is active transport.
B) Endocytosis involves engulfing materials into the cell, while exocytosis involves expelling materials out of the cell.
What is the purpose of crossing over during meiosis?
A) To ensure that chromosomes are replicated correctly
B) To increase genetic variation by exchanging genetic material between homologous chromosomes
C) To reduce the number of chromosomes in each cell
D) To separate sister chromatids into different cells
B) To increase genetic variation by exchanging genetic material between homologous chromosomes
What is a mutation in the context of genetics?
A) A change in the DNA sequence that does not affect the organism.
B) A change in the DNA sequence that can lead to a change in the protein produced.
C) A normal part of the replication process that always results in a beneficial change.
D) A process where the DNA sequence is copied without error.
B) A change in the DNA sequence that can lead to a change in the protein produced.