Bio 2 Mid-term Exam Rebate (Fall 2014)

G zero is a phase in the cell cycle where cells are not actively dividing or going through mitosis. It is a resting phase where cells can stay for a long period of time, either temporarily or permanently. During this phase, cells can perform their specific functions without dividing, such as neurons in the brain. Therefore, the correct answer is G zero.

There are 20 different amino acids found in humans. Amino acids are the building blocks of proteins and play a crucial role in various biological processes. These 20 amino acids can be combined in different sequences to form a wide variety of proteins, each with its own specific function.

The diagram of the monomer suggests that it is a nucleotide, which is the building block of nucleic acids. Nucleic acids, such as DNA and RNA, are made up of long chains of nucleotides. Therefore, the correct answer is Nucleic Acids.

Cytoplasm is the term for the jelly-like substance that is contained inside the cell membrane. It is a semi-fluid substance that fills the cell and surrounds the organelles. It is responsible for providing support to the organelles, facilitating cell movement, and serving as a site for metabolic reactions. The cytoplasm also contains various molecules and ions that are necessary for cellular processes to occur.

Enzymes are a type of protein. Proteins are large, complex molecules made up of amino acids that are essential for the structure and function of cells. Enzymes, specifically, are proteins that act as catalysts in biological reactions, speeding up the rate of these reactions without being consumed in the process. They play critical roles in various biological processes, such as digestion, metabolism, and DNA replication. Therefore, the correct answer is protein.

Calcium is a "4%" element in the body because it makes up approximately 4% of the total body weight in humans. It is an essential mineral that plays a crucial role in various bodily functions, including bone health, muscle contraction, nerve transmission, and blood clotting. Calcium is primarily stored in the bones and teeth, but it also circulates in the bloodstream, helping to maintain the proper functioning of cells and tissues throughout the body.

Calcium is not one of the top elements in the body because it is not one of the most abundant elements found in the human body. The top elements in the body include carbon, hydrogen, nitrogen, and oxygen, which are essential for the structure and function of biological molecules. Calcium, on the other hand, plays a vital role in bone and teeth health, but it is present in smaller quantities compared to the other elements mentioned.

Chlorophyll is the correct answer because it is the main light-absorbing pigment found in plant leaves. It is responsible for capturing sunlight energy during photosynthesis. Chloroplasts are the organelles in plant cells where photosynthesis takes place, and they contain chlorophyll. Thylakoids are membrane structures within chloroplasts where the light-dependent reactions of photosynthesis occur. Grana are stacks of thylakoids. While all of these options are related to the process of photosynthesis, chlorophyll specifically refers to the light-absorbing molecules that are essential for this process.

The functional group -NH2 is called the amino group. This group consists of a nitrogen atom bonded to two hydrogen atoms and is commonly found in amino acids, which are the building blocks of proteins. The amino group plays a crucial role in the formation of peptide bonds and the overall structure and function of proteins.

The main function of the Krebs cycle is to produce molecules that carry high-energy electrons to the electron transport chain. This is an important step in cellular respiration, as it generates ATP, the main source of energy for cells. The Krebs cycle breaks down pyruvate molecules and forms NADH, which carries high-energy electrons to the electron transport chain. It also produces carbon dioxide as a waste product.

In the light-dependent reactions of photosynthesis, hydrogen ions are derived from water molecules. During this process, water molecules are split, releasing oxygen gas as a byproduct and generating hydrogen ions (H+) which are used to generate ATP and NADPH. These hydrogen ions are then utilized in the photosystems to convert light energy into chemical energy. Therefore, water is the source of hydrogen ions in the photosystems of the light-dependent reactions.

Cellulose is a structural form of carbohydrate because it is a complex polysaccharide made up of repeating units of glucose molecules. It forms the main component of plant cell walls and provides structural support to plants. Starch, on the other hand, is a storage form of carbohydrate in plants, enzymes are proteins that catalyze biochemical reactions, and RNA is a nucleic acid involved in protein synthesis.

During photosynthesis, plants use carbon dioxide and water to produce glucose and oxygen. The process occurs in the chloroplasts of plant cells, where sunlight is absorbed by chlorophyll. Carbon dioxide from the air and water from the roots are converted into glucose, a sugar that serves as an energy source for the plant. Oxygen is also released as a byproduct and is released into the atmosphere. Therefore, the correct answer is glucose and oxygen.

Centrioles are cylindrical structures found only in animal cells. They play a crucial role in cell division by organizing the spindle fibers that separate the chromosomes during mitosis. Plant cells do not have centrioles, making them a feature unique to animal cells. Central vacuoles, mitochondria, and the nucleus are found in both animal and plant cells.

Chloroplasts are the organelles in plant cells responsible for photosynthesis. During photosynthesis, chloroplasts absorb sunlight through chlorophyll and convert it into chemical energy in the form of glucose. This process involves the conversion of carbon dioxide and water into glucose and oxygen. Therefore, the statement "Chloroplasts absorb sunlight and store chemical energy" best describes the process of photosynthesis.

The purpose of the light reactions is to make ATP and NADPH for use in the Calvin cycle. During the light reactions, light energy is absorbed by chlorophyll and other pigments in the thylakoid membrane of the chloroplasts. This energy is then used to convert ADP and inorganic phosphate into ATP, a form of chemical energy that can be used by the cell. Additionally, the light reactions also generate NADPH, which is a molecule that carries high-energy electrons and is used in the Calvin cycle to convert carbon dioxide into glucose.

Oxygen in cellular respiration serves the function of picking up electrons at the end of the electron transport chain. During cellular respiration, electrons are passed along a series of protein complexes in the electron transport chain, and oxygen acts as the final electron acceptor. This allows the transfer of electrons to oxygen, which then combines with hydrogen ions to form water. This process is essential for the production of ATP, the energy currency of the cell.

Oxygen is not used during glycolysis. Glycolysis is the first step in cellular respiration and it occurs in the cytoplasm of cells. It is an anaerobic process, meaning it does not require oxygen. Oxygen is used in the later steps of cellular respiration, such as the Krebs cycle and oxidative phosphorylation, where it acts as the final electron acceptor in the production of ATP.

The electron transport chain in photosynthesis is a series of proteins located in the thylakoid membrane. This chain is responsible for transferring electrons from photosystem II to photosystem I, generating a proton gradient that is used to produce ATP. The thylakoid membrane is where the light-dependent reactions of photosynthesis occur, and the proteins in the electron transport chain are embedded in this membrane. They work together to transport electrons and create the energy needed for the synthesis of ATP.

Proteins are polymers of amino acids. Amino acids are the building blocks of proteins, and they are joined together through peptide bonds to form long chains. These chains then fold into specific three-dimensional structures, which determine the function of the protein. Carbohydrates, lipids, and nucleic acids are not polymers of amino acids. Carbohydrates are composed of sugars, lipids are composed of fatty acids, and nucleic acids are composed of nucleotides. Therefore, the correct answer is protein.

The burning feeling in muscles that are working hard is caused by the accumulation of lactic acid. Carbon dioxide is produced during cellular respiration, not fermentation. Pyruvate is an intermediate product of glycolysis, not fermentation. Alcohol is produced in certain types of fermentation, such as alcoholic fermentation, but it does not cause the burning feeling in muscles. Hence, the correct answer is lactic acid.

In the light-independent reactions of photosynthesis, carbon dioxide enters the Calvin cycle and sugars are made. This is because the Calvin cycle is the part of photosynthesis where carbon dioxide is fixed and converted into glucose, a sugar molecule. This process is facilitated by the enzyme RuBisCO and occurs in the stroma of the chloroplasts. The sugars produced in the Calvin cycle are essential for the plant's energy storage and can be used for growth, reproduction, or stored as starch.

Glycolysis is the metabolic pathway that converts glucose into pyruvate. It is the first step in cellular respiration and occurs in the cytoplasm of the cell. In this process, glucose is broken down into two molecules of pyruvate, producing a small amount of ATP and NADH. The cytoplasm is the location where most of the cell's metabolic processes take place, including glycolysis. Therefore, the correct answer is cytoplasm.

Fermentation plays a crucial role in allowing glycolysis to continue producing a small amount of ATP. In the absence of oxygen, glycolysis is the only pathway available to generate ATP. Fermentation helps regenerate NAD+ from NADH, which is necessary for glycolysis to continue. Without fermentation, NADH would accumulate, and glycolysis would come to a halt. Therefore, fermentation allows the production of a small amount of ATP to sustain cellular energy production in anaerobic conditions.

Fermentation is a metabolic process that occurs in the absence of oxygen. It is an anaerobic process, meaning it does not require oxygen. During fermentation, electron transport chain is not involved. Instead, it is a process that involves the partial breakdown of glucose to produce energy in the absence of oxygen. Therefore, the phrase "uses electron transport chain" is incorrect.