Module 7: Cell Structure and Function

Module 7: Cell Structure and Function

• Module covers cell structure and function
• Presented by Br. Farhan Kamili

Build to Performance Expectations

• HS-LS1-1: DNA structure determines protein structure, which carries out life's essential functions in specialized cells
• HS-LS1-5: Photosynthesis transforms light energy into stored chemical energy (illustrated via a model)
• HS-LS3-1: Clarify the role of DNA and chromosomes in coding instructions for traits from parents to offspring
• HS-LS1-3: Investigate evidence that feedback mechanisms maintain homeostasis, focusing on osmosis

Lesson 4: Cell Structures and Organelles

• Focus Question: Structures and functions in prokaryotic and eukaryotic cells

New Vocabulary

• cytoplasm
• cytoskeleton
• centriole
• cilium
• flagellum
• cell wall
• mitochondrion
• chloroplast
• ribosome
• nucleolus
• endoplasmic reticulum
• Golgi apparatus
• vacuole
• lysosome

Moving into the cell

• Discussion of prokaryotic and eukaryotic cell interiors compared to the exteriors (plasma membrane and cellular transport methods).
• Prokaryotes and eukaryotes have different internal structures and organelles, although they share some similarities.

Prokaryotic vs Eukaryotic Cells

• Visual representation comparing prokaryotic and eukaryotic cells, illustrating differences and commonalities in components

Common structures between cell types

• Prokaryotes and eukaryotes share some common structures
• All prokaryotes and eukaryotes contain a plasma membrane, cytoplasm, cytoskeleton, and ribosomes.
• Some eukaryotes and prokaryotes contain cell walls.

Common structures - Plasma membrane

• This slide discussed plasma membrane, a topic already covered in another section.

Common structures - Cytoplasm

• Cytoplasm (a semifluid substance) is the site of all chemical reactions in prokaryotes
• Eukaryotes have organelles within their cytoplasm that carry out these reactions.

Common structures - Cytoskeleton

• The cytoskeleton supports and shapes the cell. Its components include microtubules, microfilaments (also known as actin filaments), and centrioles.
• Microtubules are hollow and form a rigid skeleton.
• Microfilaments provide shape and enable movement
• Centrioles are important during cell division.

Common structures - Ribosomes

• Ribosomes manufacture proteins—the cell's workers.
• Unlike other organelles, ribosomes are not membrane-bound.
• Only eukaryotes have membrane-bound organelles.

Common structures - Cell wall

• All prokaryotes and some eukaryotes have cell walls,
• Cell walls are thick, rigid meshes surrounding plasma membranes.
• Plant cell walls contain cellulose ; prokaryotic walls contain peptidoglycans.

Common structures – Flagella

• Flagella are external structures made of microtubules.
• Used for movement.
• Present in both prokaryotes and some eukaryotes.
• Eukaryotes also have cilia, which aid in movement.

Prokaryote Structures

• Some prokaryotes also have pili (filament structures) and capsules (a carbohydrate covering).
• Capsules aid in adhesion, movement, and DNA transfer.
• Pili help with attachment and movement.

Eukaryote Structures

• Eukaryotes have other membrane-bound organelles besides those already mentioned.

Nucleus – Controlling Cell Activities

• The nucleus contains most of the cell's DNA, which stores information to create proteins. This is essential for cell growth, function, and reproduction.
• The nucleus is surrounded by a double membrane called a nuclear envelope.

Mitochondria – Processing Energy

• Mitochondria convert sugar particles into ATP (usable energy).
• They have an outer membrane and a highly folded inner membrane that maximises surface area for breaking down sugar bonds.

Chloroplasts – Processing Energy

• Chloroplasts are in plant cells and some other eukaryotes.
• Capture light energy and convert to chemical energy via photosynthesis
• Chloroplasts contain thylakoids that contain chlorophyll.

Endoplasmic Reticulum – Manufacturing Proteins

• The endoplasmic reticulum (ER) is a membrane system of sacs and channels.
• Involved in protein and lipid synthesis.
• Includes Rough ER (site of protein production) and Smooth ER (site of carbohydrate and lipid production).

Golgi Apparatus – Processing, Transporting, and Storing Molecules

• The Golgi apparatus modifies, sorts, and packages proteins.
• Using vesicles, proteins are transported to other parts of the cell.

Vacuole – Processing, Transporting, and Storing Molecules

• Vacuoles are membrane-bound sacs involved in storage (food, enzymes, waste).
• Often larger in plants than in animal cells.

Lysosomes – Processing, Transporting, and Storing Molecules

• Lysosomes contain digestive enzymes that break down excess or damaged organelles and foreign substances.

Comparing Cells

• Only plant cells have chloroplasts, vacuoles, and cell walls.

Organelles at Work

• Knowledge of organelle functions provides increased understanding of cellular processes
• The process of protein synthesis and distribution across organelles is discussed.

Do Nows/TWS (Multiple Choice Questions)

• Series of questions about cell structures, their features, and locations in various cell types.