Chapt 6 BIOL 1406

Describe the endosymbiotic theory

posits that some eukaryotic cell organelles, such as mitochondria and plastids, evolved from free-living prokaryotes.

How is this similar/different from the path of a hydrolytic enzyme?

split different groups of biomolecules such as esters, peptides and glycosides. Hydrolytic enzymes break down protein, lipids, nucleic acids, carbohydrate and fat molecules into their simplest units.

What three unique characteristics do both mitochondria and chloroplasts possess? What type of cell is each found in?

Chloroplasts: - Only in plant cells - Makes sugar (stored energy) - Needs to absorb sunlight, so must have chlorophyll Mitochondria: - Both plant and animal - Releases usable energy from sugar - Does not need sunlight

What does each do in the context of cell function cont?

Extracellular Matrix - Cell: Animal - Function: helps cells attach to, and communicate with, nearby cells, and plays an important role in cell growth, cell movement, and other cell functions. Cytoskeleton: Centrosomes/Centrioles - Cell: Animal - Function: centrioles are critical to allow the mitotic spindle to form, which is critical to allow cytokinesis. Flagella - Cell: Animal & plants - Function: enables movement and chemotaxis Cilia - Cell: Animal & plants - Function: to move water relative to the cell in a regular movement of the cilia. Plasmodesmata: In multicellular organisms, cells must be able to communicate with each other. found in PLANTS Tight junctions - Cell: Animal & plants - Function: form the continuous intercellular barrier between epithelial cells Desmosomes - Cell: Animal & plants - Function: represent major intercellular adhesive junctions at basolateral membranes of epithelial cells and in other tissues. Gap junctions - Cell: Animal & plants - Function: aggregates of intercellular channels that permit direct cell-cell transfer of ions and small molecules.

What does each do in the context of cell function?

Nucleus - Cell: Animal & Plant - Function: Holds genetic information and as the cell's control center. Ribosomes - Cell: Animal, plant, & bacteria - Function: the site of protein synthesis in the cell. Endoplasmic Reticulum: Smooth ER - Cell: Animal & Plant - Function: production and metabolism of fats and steroid hormones. Rough ER - Cell: Animal & Plant - Function: production, folding, quality control and despatch of some proteins. Golgi Apparatus: - Cell: Animal & Plant - Function: transport, sorting and modification of both protein and lipids. Lysosomes: - Cell: Animal & Plant - Function: the digestive system of the cell, serving both to degrade material taken up from outside the cell and to digest obsolete components of the cell itself Vacuoles: - Cell: Animal & Plant - Function: In Animal, Plasma Membrane or Cell membrane: - Cell: Animal & Plant - Function: In animal cells, vacuoles are generally small and help sequester waste products. In plant cells, vacuoles help maintain water balance. Peroxisomes: - Cell: Animal & Plant - Function: They contain digestive enzymes for breaking down toxic materials in the cell and oxidative enzymes for metabolic activity. Chloroplasts: - Cell: Plants - Function: produce energy through photosynthesis and oxygen-release processes, which sustain plant growth and crop yield Mitochondria: - Cell: Animal & Plant - Function: generates ATP by utilizing the energy released during the oxidation of the food we eat. Cell wall: - Cell: Plant - Function: provides tensile strength and protection against mechanical and osmotic stress

Compare and contrast animal vs. plant cells

Plant: - Cell wall - Large vacuole - Chloroplasts - flagella in gametes Animal: - NO cell wall - small or no vacuole - NO chloroplasts - flagella Both: - Plasma membrane - ER - Mitochondria - Nucleus - Golgi apparatus

What are the cell junctions?

Plasmodesmata: gap like junction for plants. Gap Junction: transfer cell signals and nutrients Desmosomes: fasten cells together Makes seals between cells which keeps fluid from leaving through.

Compare and contrast prokaryotic vs. eukaryotic cells

Prokaryotic: - No nucleus - Small size - Unicellular - No membrane bound organelles - Examples: Bacteria & Archaea Eukaryotic: - Has nucleus - Large size - Cell wall has chitin or cellulose - Unicellular or multicellular - Membrane bound organelles - Examples: Humans, plants, fungi, and protists. Both: - Contain DNA - Contain ribosomes - Have cell membrane - Contain cytoplasm

Trace the path of a secreted or membrane bound protein, from production to completion. Include the name of this pathway and the organelles are involved?

Secretory Pathway: - rough ER → Golgi → secretory vesicles → cell exterior. - refers to the endoplasmic reticulum, Golgi apparatus and the vesicles that travel in between them as well as the cell membrane and lysosomes

How is surface area calculated and how is volume calculated? What is the effect of cell growth on the surface area/volume ratio (in other words, what is the relationship between these two)? Do cells maintain a HIGH or LOW surface area/volume ratio? Why?

Surface area: h x w x sides Volume: h x w x l - SA increases, volume stays constant - As a cell increase in size, SA to Volume ratio decreases due to less surface area to grow.

What plant organelle allows a cell to exceed normal cell size limitations, and how does it accomplish this?

Vacuoles can allow for growth.