Lysosomes and Peroxisomes

These flashcards cover key vocabulary terms and definitions related to lysosomes and peroxisomes, focusing on their structure, function, and significance in cellular biology.

Lysosomes

Membrane bound organelles containing digestive enzymes.

Eukaryotic cells

Cells that contain a nucleus and organelles enclosed within membranes.

Acidic pH

The pH level necessary for lysosomal enzymes to function optimally.

De Duve

The scientist who discovered lysosomes in 1955.

Digestive enzymes

Enzymes that break down biological macromolecules.

Acid hydrolases

Enzymes that require an acidic environment to digest substrates.

Primary function of lysosomes

Digestion of cellular waste and macromolecules.

Lysosomal membrane

The membrane that encloses lysosomes and contains specific membrane proteins.

LAMPs

Lysosomal associated membrane proteins that protect the lysosomal membrane.

LIMP

Lysosomal integral membrane proteins that contribute to the lysosome's stability.

V-ATPase

An ATP-dependent proton pump that creates an acidic environment in lysosomes.

Pleiomorphism

The ability of lysosomes to vary in size and shape.

Lysosome biogenesis

The process by which lysosomes are formed from the Golgi apparatus.

Mannose-6-phosphate

A tag that directs lysosomal enzymes to their destination.

Autophagy

A process for degradation of organelles and proteins to maintain cellular homeostasis.

Autolysis

The digestion of parent cells by their own lysosomes.

Fertilization process

Involves the secretion of enzymes from the sperm acrosome to penetrate the egg.

Heterophagy

Lysosomal digestion of extracellular materials through endocytosis.

Programmed cell death

Controlled cell death facilitated by lysosomal enzyme release.

Cathepsins

Proteases that play a role in lysosomal-mediated cell death.

Lysosomal Storage Diseases

Disorders resulting from defective lysosomal function.

Peroxisomes

Single membrane-bound organelles involved in the degradation of hydrogen peroxide.

Catalase

An enzyme present in peroxisomes that breaks down H2O2 into water and oxygen.

Urate oxidase

An enzyme involved in urate metabolism, specific to some species, and absent in humans.

Beta-oxidation

A metabolic process whereby fatty acids are broken down in peroxisomes.

Peroxisomal disorders

Conditions resulting from enzyme dysfunctions in peroxisomes.

Glyoxysomes

Specialized peroxisomes in plants that aid in fatty acid conversion to carbohydrates.

Glyoxylate cycle

A pathway allowing plants to convert fatty acids into carbohydrates.

Photorespiration

A process that occurs in plants and involves peroxisomal metabolism.

Enzymatic function in lysosomes

Involves the breakdown of various biological molecules.

Examples of lysosomal enzymes

Acid phosphatase, ribonuclease, acid deoxyribonuclease.

Proteases in lysosomes

Enzymes that degrade proteins such as Cathepsin and Collagenase.

Function of peroxisomes

Degradation of hydrogen peroxide and lipid metabolism.

ABC transporters

Proteins that facilitate the entry of substances into peroxisomes.

VLCFA

Very long chain fatty acids processed primarily in peroxisomes.

Synthesis in peroxisomes

Involves the production of cholesterol and bile acids.

ATP generation in peroxisomes

Not the primary role; mainly involved in biosynthesis.

Comparative metabolism

Differences between mitochondrial and peroxisomal fatty acid degradation.

Cytoplasmic protein import

Process of importing proteins into peroxisomes.

Function of glyoxysomes

Convert fatty acids to carbohydrates during seed germination.

Regulation of peroxisome function

Influenced by cellular energy status and nutrient availability.

Importance of LAMPs and LIMPs

Protect lysosomal membranes from degradation.

Lysosomal swelling detect

Indicates premature enzyme activation and potential cell damage.

Receptor-mediated endocytosis

Method of ingesting extracellular molecules into lysosomes.

Lysosomal enzyme synthesis

Occurs in ribosomes and is tagged for lysosomal targeting.

Cellular homeostasis maintenance

Achieved through autophagy and degradation of dysfunctional organelles.

Acrosome function during fertilization

Secretes enzymes that allow sperm to penetrate the egg.

Role of oxygen in peroxisome action

Essential for the degradation of substrate toxins.

Function of plasmalogen synthesis

Significant for cell membranes in the nervous and immune systems.