Chapter 7 - Inside the Cell

Flashcards for Chapter 7 - Inside the Cell, covering prokaryotic and eukaryotic cells, organelles, the endomembrane system, macromolecular recycling, mitochondria and chloroplasts, endosymbiosis, microtubules, microfilaments, intermediate filaments, cilia and flagella, motor proteins, and cellular motility.

Compare and contrast prokaryotic cells and eukaryotic cells

• Prokaryotic: no nucleus, smaller, few organelles, DNA in nucleoid, mostly unicellular.

• Eukaryotic: nucleus, larger, many organelles, DNA in nucleus, can be unicellular or multicellular.

Explain at least three ways in which organelles increase metabolic efficiency in eukaryotic cells

1. Compartmentalization allows separation of incompatible reactions.

2. Concentrates substrates and enzymes, increasing reaction rates.

3. Provides surfaces for specific biochemical reactions (e.g., membranes).

List three organelles that are present in plant cells but not animal cells

1. Chloroplasts 2. Central vacuole 3. Cell wall

Describe the structure and function of the nucleus

Structure: Double membrane (nuclear envelope), nuclear pores, nucleolus.

Function: Stores DNA, coordinates cell activities like growth, metabolism, and reproduction.

Describe the structure and function of each of the components of the endomembrane system, and explain how these components work together in the secretory pathway

Components: Rough ER, Smooth ER, Golgi apparatus, lysosomes, vesicles. Secretory Pathway: Protein made in rough ER → processed in Golgi → transported via vesicles to destination (e.g., plasma membrane or lysosome).

Explain the process by which a ribosome becomes bound to the rough endoplasmic reticulum and synthesises a protein into the lumen

1. Ribosome begins translation in cytosol. 2. Signal peptide emerges, binds to SRP. 3. SRP directs complex to ER. 4. Ribosome docks, protein fed into ER lumen, signal peptide removed.

List at least 3 general destinations for proteins made in the endomembrane system

1. Lysosomes 2. Plasma membrane 3. Secreted outside the cell

Describe three pathways for macromolecular recycling via lysosomes

1. Autophagy: recycling damaged organelles.

2. . Phagocytosis: engulfing large particles.

3. Receptor-mediated endocytosis: specific uptake of molecules.

Compare and contrast the structure and function of mitochondria and chloroplasts

• Mitochondria: site of ATP production; double membrane; cristae; found in all eukaryotes.

• Chloroplasts: site of photosynthesis; double membrane + thylakoids; found in plants/algae.

Discuss the evidence for endosymbiosis

1. Mitochondria/chloroplasts have their own DNA.

2. Double membranes.

3. Reproduce independently by binary fission.

4. Have their own ribosomes.

Compare and contrast the structure and function of microtubules, microfilaments, and intermediate filaments

• Microtubules: hollow tubes, cell shape, vesicle transport, chromosome movement. - Microfilaments: actin-based, cell shape, muscle contraction, cytoplasmic streaming. -

• Intermediate filaments: fibrous, structural support, anchor organelles.

Describe the general structure of cilia and flagella, and explain how bending in these appendages is generated

Structure: 9+2 microtubule arrangement anchored by basal body. Bending: Caused by dynein motor proteins that 'walk' along adjacent microtubules, causing them to slide and bend.

Compare and contrast the function of kinesin, dynein, and myosin motor proteins with regards to organelle transport

• Kinesin: moves vesicles toward microtubule plus end (cell periphery). -

• Dynein: moves vesicles toward minus end (cell center). -

• Myosin: moves along actin filaments, drives muscle contraction and cytoplasmic streaming.

Describe at least 5 ways in which microfilaments and myosin proteins interact to generate cellular motility

1. Muscle contraction.

2. Cytokinesis in animal cells.

3. . Cytoplasmic streaming.

4. Cell crawling.

5. Vesicle transport.