Biology Flashcards

The carbon dioxide produced during cellular respiration is

Answer: taken out

During cellular respiration, glucose is oxidized to produce energy (ATP), and carbon dioxide (CO2) is generated as a metabolic waste product. This CO2 is transported by the blood to the lungs, where it is subsequently expelled from the body through the process of exhalation. Therefore, the carbon dioxide produced is taken out.

Which process produces oxidative phosphorylation?

Answer: ATP in respiration

Oxidative phosphorylation is the metabolic pathway that generates the vast majority of ATP during aerobic respiration. This process occurs in the mitochondria, where energy released from the electron transport chain is used to power the synthesis of ATP from ADP and inorganic phosphate. It is the most efficient method of ATP production in cells.

What is glycolysis' final result?

Answer: Pyruvic acid

Glycolysis is the initial metabolic pathway in cellular respiration, occurring in the cytoplasm. During this process, one molecule of glucose, a six-carbon sugar, is broken down into two molecules of pyruvic acid, a three-carbon compound. Therefore, pyruvic acid is the final result of glycolysis.

The connection between the Krebs cycle and glycolysis is modified before pyruvate enters the cycle to

Answer: Acetyl CoA

Before pyruvate, the end product of glycolysis, can enter the Krebs cycle (also known as the citric acid cycle), it undergoes an intermediate step called pyruvate oxidation. In this step, pyruvate is converted into Acetyl CoA, a two-carbon molecule that then condenses with oxaloacetate to begin the Krebs cycle. Acetyl CoA thus serves as the crucial link between glycolysis and the Krebs cycle.

NADP+ conversion to NADPH is reduced in

Answer: Calvin cycle

The Calvin cycle is the set of light-independent reactions in photosynthesis where carbon dioxide is fixed and converted into glucose. This process requires reducing power, which is supplied by NADPH. Specifically, NADPH is utilized to reduce 3-phosphoglycerate to glyceraldehyde-3-phosphate, providing the electrons necessary for carbohydrate synthesis within the cycle.

Select the false statement about the Krebs cycle.

Answer: cycle starts with condensation of acetyl group with pyruvic acid to produce citric acid

The Krebs cycle begins with the condensation of a two-carbon acetyl group from Acetyl CoA with a four-carbon oxaloacetate molecule to form a six-carbon citric acid. The statement incorrectly claims the cycle starts with pyruvic acid; pyruvic acid is first converted to Acetyl CoA in an intermediate step before entering the cycle. Therefore, this statement is false.

For every glucose molecule that enters the cell, 38 ATP molecules are used to store ________ of energy.

Answer: 686 Kcal

The complete oxidation of one mole of glucose during cellular respiration releases a total of approximately 686 Kcal of energy. While not all of this energy is captured in the form of ATP, the formation of 38 ATP molecules represents the cell's efficient mechanism for storing a significant portion of this released energy for various cellular activities.

Which of these is the ultimate respiratory substrate and produces the most ATP molecules?

Answer: Glucose

Glucose is considered the ultimate and most common respiratory substrate for cellular respiration in most organisms. It is efficiently broken down through glycolysis, the Krebs cycle, and oxidative phosphorylation to produce the largest number of ATP molecules compared to other substrates. This makes it the primary and most efficient energy source for cells.

In cellular respiration, the CH bond of food is broken down by

Answer: oxidation

Cellular respiration is fundamentally an oxidative process where the energy stored in the C-H bonds of food molecules, such as glucose, is released. During this process, electrons are progressively removed from glucose through a series of oxidation reactions and transferred to electron carriers, ultimately leading to the synthesis of ATP. The breaking of C-H bonds and removal of electrons define this oxidation.

The incomplete oxidation of glucose into pyruvic acid, which involves numerous intermediate processes, is known as .

Answer: Glycolysis

Glycolysis is the metabolic pathway that initiates cellular respiration by breaking down one molecule of glucose (a six-carbon sugar) into two molecules of pyruvic acid (a three-carbon compound). This process involves a series of ten enzyme-catalyzed reactions and represents the incomplete oxidation of glucose, occurring in the cytoplasm without the need for oxygen.

This trait of a hormone prevents it from exerting its full action in the absence of another hormone.

Answer: permissiveness

Permissiveness describes a hormonal interaction where one hormone cannot exert its full biological effects without the prior or concurrent presence of another hormone. For instance, thyroid hormone is permissive to the actions of epinephrine, enhancing its ability to stimulate fat breakdown, even though thyroid hormone itself doesn't directly cause significant fat breakdown.

Where is the "hormone response element" located on the cell?

Answer: DNA

Hormone response elements (HREs) are specific DNA sequences located in the promoter regions of target genes. Intracellular hormone receptors, typically activated by lipid-soluble hormones like steroids or thyroid hormones, bind to these HREs. This binding then directly regulates the transcription of the associated gene, either activating or repressing its expression.

This organ is neuroendocrine.

Answer: hypothalamus

The hypothalamus is a critical neuroendocrine organ because it serves as the primary link between the nervous and endocrine systems. It receives neural signals and, in response, produces and secretes various releasing and inhibiting hormones that control the secretion of hormones from the anterior pituitary gland. It also produces ADH and oxytocin, which are stored and released by the posterior pituitary.

Which of these does the hormone classification by their chemical makeup not include?

Answer: glucose containing hormones

Hormones are chemically classified into major groups based on their structure, including steroid hormones (derived from cholesterol), amino acid-derived hormones (like catecholamines and thyroid hormones), and peptide/protein hormones (chains of amino acids). 'Glucose containing hormones' is not a recognized chemical classification for hormones.

The responsibility for new messenger RNA transcription is taken up by .

Answer: steroid hormones

Steroid hormones are lipid-soluble and can readily diffuse across the cell membrane to bind with specific intracellular receptors. The hormone-receptor complex then translocates to the nucleus, where it binds to specific DNA sequences (hormone response elements). This binding directly regulates gene expression by initiating or repressing the transcription of new messenger RNA (mRNA), thereby altering protein synthesis within the cell.

The release of the sympathetic nerve impulses

Answer: epinephrine

Sympathetic nerve impulses are part of the 'fight or flight' response, which prepares the body for immediate action. This response involves the release of hormones from the adrenal medulla, primarily epinephrine (also known as adrenaline) and norepinephrine. These hormones increase heart rate, blood pressure, and glucose levels to mobilize energy and enhance alertness.