CELL STRUCTURE AND FUNCTION

Published on
Embed video
Share video
Ask about this video

Scene 1 (0s)

[Virtual Presenter] CELL STRUCTURE AND FUNCTION. CELL STRUCTURE AND FUNCTION.

Scene 2 (6s)

[Audio] LESSON OBJECTIVES Identify the parts of prokaryotic and eukaryotic cells and their basic structures through diagrams or models. Describe the functions of major cell organelles such as the nucleus, mitochondria, ribosomes, and cell membrane. Compare and contrast prokaryotic and eukaryotic cells, as well as plant and animal cells, based on structure and function..

Scene 3 (32s)

[Audio] PROKARYOTIC CELL The word "Prokaryotic" comes from Greek roots: "Pro-" → means "before" "Karyon" → means "nut" or "kernel", referring to the nucleus So, Prokaryotic = "Before nucleus" No true nucleus (DNA is free-floating in the BACTERIA cytoplasm) No membrane-bound organelles Generally smaller and simpler in structure Cell wall present (usually made of peptidoglycan) Reproduce asexually (binary fission) Examples: Bacteria and Archaea ARCHAEA.

Scene 4 (1m 8s)

[Audio] Feature Description Nucleus ❌ No true nucleus. DNA is in a region called the nucleoid Size Small (0.1 to 5 micrometers) Organelles ❌ No membrane-bound organelles (like mitochondria, ER, etc.) Cell division Reproduces by binary fission (asexual reproduction) DNA shape Circular DNA (often one chromosome) Cell wall ✅ Present (made of peptidoglycan in bacteria) Examples Bacteria, Archaea.

Scene 5 (1m 45s)

[Audio] EUKARYOTIC CELLS  The word "Eukaryotic" also comes from Greek roots: "Eu-" → means "true" or "good" "Karyon" → means "nut" or "kernel", referring to the nucleus So, Eukaryotic = "True nucleus" These are larger and more complex cells with a nucleus. The DNA is enclosed inside the nucleus. They contain membrane-bound organelles like mitochondria, Golgi apparatus, etc. Example: Plant cells, animal cells, fungi, and protists.

Scene 6 (2m 22s)

[Audio] Feature Prokaryotic Cells Eukaryotic Cells Nucleus ❌ No true nucleus (DNA in nucleoid) ✅ True nucleus with nuclear membrane Size Small (0.1 – 5 µm) Larger (10 – 100 µm) DNA Structure Circular DNA, single chromosome Linear DNA, multiple chromosomes Organelles No membrane-bound organelles Has membrane-bound organelles (e.g., mitochondria) Cell Division Binary fission Mitosis or meiosis Examples Bacteria, Archaea Plants, Animals, Fungi, Protists Cell Wall Present (made of peptidoglycan in bacteria) Present in plants and fungi (cellulose or chitin) Ribosomes Small (70S) Larger (80S) Complexity Simple structure Complex structure Plasmids Often present Rare or absent Reproduction Asexual (binary fission) Sexual or asexual First Appeared ~3.5 billion years ago ~2 billion years ago.

Scene 7 (3m 36s)

[Audio] Capsule: Outer protective layer (not in all prokaryotes) Cell Wall: Provides structural support Cell Membrane: Regulates entry and exit of substances Cytoplasm: Jelly-like fluid where reactions occur Ribosomes: Site of protein synthesis (not membrane-bound) Nucleoid Region: Area containing the single circular DNA strand Plasmids: Small circular DNA molecules (often carry genes for antibiotic resistance) Flagella/Pili: Aid in movement and attachment.

Scene 8 (4m 15s)

[Audio] PARTS OF THE CELL ( OVERVIEW ) Cell Membrane Cytoplasm Nucleus Mitochondria Ribosomes Endoplasmic Reticulum (Smooth and Rough) Golgi Apparatus Lysosomes Vacuoles Chloroplasts (plants only) Cell Wall (plants only) Cytoskeleton.

Scene 9 (4m 36s)

[Audio] Cell Membrane Structure: Phospholipid bilayer with proteins Function: Protects cell, controls movement of substances in/out Key Term: Selective permeability.

Scene 10 (4m 49s)

[Audio] Nuclear Envelope: A double membrane that surrounds the nucleus and separates it from the cytoplasm; contains nuclear pores for material exchange. Nucleolus: A dense region within the nucleus where ribosomal RNA (rRNA) is produced and ribosome assembly begins. Chromatin: Uncondensed DNA and protein complex; becomes chromosomes during cell division. Nuclear Pores: Openings in the nuclear envelope that control the movement of molecules between the nucleus and cytoplasm. Nucleus Structure: Nuclear membrane, nucleolus, chromatin Function: Control center of the cell, stores DNA Fun Fact: Only in eukaryotic cells.

Scene 11 (5m 37s)

[Audio] Outer Membrane: Smooth membrane that encloses the entire organelle and acts as a barrier between the cytosol and the inner environment. Inner Membrane: Folded into structures called cristae; contains proteins for the electron transport chain and ATP synthesis. Cristae: Folds of the inner membrane that increase surface area for energy production. Matrix: The innermost compartment of the mitochondrion; contains enzymes for the Krebs cycle, mitochondrial DNA, and ribosomes. Intermembrane Space: The space between the inner and outer membranes where proton gradient is established for ATP production. Mitochondria Function: Site of cellular respiration; produces ATP Structure: Double membrane with inner folds (cristae) Nickname: Powerhouse of the cell.

Scene 12 (6m 33s)

[Audio] Ribosomes Function: Protein synthesis Location: Floating in cytoplasm or attached to rough ER Structure: Small and dense, no membrane.

Scene 13 (6m 45s)

[Audio] Endoplasmic Reticulum Smooth ER: Synthesizes lipids, detoxifies chemicals Rough ER: Covered with ribosomes, synthesizes proteins Structure: Network of membranes connected to nuclear envelope.

Scene 14 (7m 0s)

[Audio] Cisternae: Flattened, stacked membrane sacs that process and package proteins. Cis Face: The receiving side of the Golgi apparatus, located near the ER; receives transport vesicles. Trans Face: The shipping side of the Golgi apparatus; sends modified proteins to their destination. Transport Vesicles: Small membrane-bound sacs that carry materials to and from the Golgi. Golgi Apparatus Function: Modifies, sorts, and packages proteins for transport Structure: Stacked, flattened membranes Analogy: Post office of the cell.

Scene 15 (7m 41s)

[Audio] Lysosomes Function: Digests worn-out cell parts, invaders Structure: Membrane-bound sac with enzymes Present in: Animal cells mostly.

Scene 16 (7m 53s)

[Audio] Vacuoles Function: Storage of water, nutrients, and waste Large central vacuole in plant cells helps maintain turgor pressure.

Scene 17 (8m 3s)

[Audio] Outer Membrane: Smooth outer layer that protects the organelle. Inner Membrane: Lies just inside the outer membrane and regulates passage of materials. Stroma: The fluid-filled space inside the inner membrane; contains enzymes for the Calvin cycle, DNA, and ribosomes. Thylakoids: Disc-shaped membrane-bound structures where light-dependent reactions occur. Granum (plural: Grana): Stack of thylakoids that increases surface area for photosynthesis. Lamellae: Thin membranes connecting grana, helping maintain their structure and alignment. Chlorophyll: The green pigment embedded in thylakoid membranes that captures light energy. Chloroplasts (Plant Cells Only) Function: Site of photosynthesis Structure: Contains chlorophyll, double membrane, internal thylakoids.

Scene 18 (9m 2s)

[Audio] Cell Membrane Phospholipid bilayer Semi-permeable – controls entry and exit Function: Protection, communication.

Scene 19 (9m 13s)

[Audio] Cell Wall (Plants Only) Found outside the cell membrane Made of cellulose Provides structure and support.

Scene 20 (9m 22s)

[Audio] Cytoplasm Jelly-like fluid Suspends organelles Site of many metabolic reactions.

Scene 21 (9m 29s)

Plant Cell & Cell Rough Endoplasmic Reticulum Nucleus Ribosomes Microbody Cell Wall Smooth Endoplasmic Reticulum Mitochondria Golgi Apparatus Chloroplast Vacuole Plasma Membrane Microtubules Golgi Complex Reticulum Diagram Nuclear membrane Microvilli Nucleolus Mitochondria Rough Endoplasmic Plasma Memrane.

Scene 22 (9m 36s)

[Audio] StructurePlantCellAnimalCellCellWallPresentAbsentChloroplastsPresentAbsentVacuoleLargeCentralSmallorabsentShapeRectangularRounded.

Scene 23 (9m 50s)

ASSESSMENT.