Cellular Metabolism and ATP

Cellular Metabolism

• Cellular metabolism refers to all chemical reactions occuring in a cell
• Catabolic reactions break down complex molecules into simpler molecules, releasing energy.
• Anabolic reactions build complex molecules from simpler ones, requiring energy.
• Photosynthesis is an anabolic reaction
• Anabolic and catabolic reactions are coupled by ATP.

ATP

• ATP hydrolysis releases potential energy.
• ATP is hydrolyzed to ADP + Pi + free energy.
• The energy released from ATP hydrolysis is used by anabolic reactions to build organic molecules.
• Catabolic reactions release energy which is stored as ATP.
• ATP powers anabolic reactions.
• This is energy coupling: energy from exergonic reactions fuels endergonic reactions.
• ATP is a renewable resource.

Phosphorylation

• ATP hydrolysis transfers a phosphate group to a reactant, which is called phosphorylation.
• Phosphorylation makes reactants more reactive by increasing their free energy.
• This energy is used to drive chemical, transport and mechanical work.

Cellular Reactions: Enzymes

• Enzymes are proteins that act as catalysts.
• Catalysts speed up the rate of a reaction without being consumed in the process.
• Enzymes are reusable.
• Enzymes are critical for life's reactions, as they speed up processes that would otherwise be too slow.

Human Development

• Humans are animals, and begin as zygotes.
• Between the zygote and newborn stages, human cells undergo 41 mitotic divisions.
• This results in 2⁴¹ (more than 2 trillion) cells.
• Human cells differentiate, resulting in a newborn with over 2 trillion cells that form tissues, organs and organ systems.

Anatomy and Physiology

• Anatomy is the study of structures and their relationships.
• Physiology is the study of how body structures function.

Animal Structure

• Animal structure has a hierarchy.
• There is a close relationship between structure and function.

Adaptions for Flight

• Forelimbs are modified as wings with light-weight keratin feathers.
• Strong pectoral muscles are anchored to a keel (sternum).
• Reduction in mass of some organs.
• Lungs with air sacs.
• Four-chambered heart.
• Extended vision and coordination.

Phenotype

• Phenotype is observable traits.
• An organism's phenotype reflects the relationship between genotype and environment.
• Natural selection only acts on phenotype.

Nervous and Endocrine system

• Nerve impulses cause rapid, short-term responses.
• Hormones usually cause slower but longer-lasting responses.

Feedback Loops

• Feedback loops help maintain homeostasis.
• A system needs a sensor to detect changes, a control center to coordinate a response, and an effector to exert a response.

Negative Feedback

• Negative feedback opposes the initial stimulus.
• This brings internal conditions back to a tolerable range.
• The control center determines the set point, compares input with the normal range, and activates the effector if needed.

Blood Glucose Regulation

• Blood glucose levels are tightly regulated by two pancreatic hormones.
• Glucagon increases blood glucose by stimulating cells to release glucose into the blood, thus raising blood glucose.
• Insulin stimulates cells to take glucose out of the blood and store it, thus lowering blood glucose.

Digestive System

• Animals eat for organic molecules, essential nutrients and fuel for cellular respiration.
• Organic molecules are needed to synthesize new molecules.
• Essential nutrients are those the organism cannot make on its own (e.g, essential vitamins and minerals).

Cellular Respiration

• Cellular respiration is the process of breaking down glucose to produce ATP.
• This process has three stages: glycolysis, citric acid cycle and electron transport chain (not stated in the text).
• Glycolysis occurs in the cytoplasm of all cells.
• The citric acid cycle occurs in the cytoplasm of prokaryotes and the matrix of mitochondria in eukaryotes.
• Electron transport chain occurs in the inner membrane of mitochondria (not stated in the text).

Digestive Compartments

• Most animals have a specialized digestive tract.
• Food is digested in organ compartments that house hydrolytic enzymes.
• Some animals have a sac with a single opening called a gastrovascular cavity (e.g., hydra).

Alimentary Canal

• Most animals have an alimentary canal.
• Alimentary canal is a tube that runs between two openings.
• The alimentary canal is divided into compartments that process food sequentially.
• These compartments include: pharynx, esophagus, crop, stomach, gizzard, intestine, and anus.
• The crop stores food pre-digestion.
• The gizzard grinds food.

Explore the dynamic world of cellular metabolism, focusing on the roles of catabolic and anabolic reactions. Learn how ATP hydrolysis and phosphorylation facilitate energy transfers within cells, powering various biochemical processes. This quiz delves into the essential concepts of energy coupling and the importance of ATP in cellular functioning.