Cell Structure and Function -...

Cell Structure and FunctionChapter 4

Saturday, January 1, 2011

Chapter 4: Cell Structure

• Section 1: “The History of Cell Biology”

• Section 2: “Introduction to Cells”

• Section 3: “Cell Organelles and Features”

• Section 4: “Unique Features of Plant Cells”


Discovery of Cells• 1665 - Robert Hooke discovered

cells in cork

• 1673 - Leeuwenhoek was the first to view live cells under a ‘scope

• 1838 - Matthias Schleiden discovered cells in all plants

• 1839 - Theodor Schwann discovered cells in all animals

• 1858 - Ruldolph Virchow discovered cells can only come from cells


Cell Theory

• All living things are made up of one or more cells

• Cells are the basic unit of structure and function in organisms

• All cells arise from existing cells


Structure and Function• A cell’s shape reflects its function

• cells are limited by surface-area-to-volume ratio

• small surface-area-to-volume ratio helps with:

• exchanging material with surroundings

• less waste/needs less nutrients


Prokaryotic Cell• no nucleus (Pro = No!),

genetic material is free-floating

• no membrane-bound organelles

• cell membrane: cell’s outer boundary

• ribosome: makes proteins

• cytoplasm: fluid in the cell

• flagella: for movementSaturday, January 1, 2011

Prokaryotic Cell


Eukaryotic Cell

• DNA inside nucleus

• membrane-bound organelles carry out specific functions in the cell


Prokaryotic vs. Eukaryotic


Organization• Plants: Cell Leaf Tissue Leaf

• Humans: Cell Lung Tissue Lung Respiratory System

TISSUECELL ORGANORGANSYSTEM


Organization

• Tissue: distinct group of cells

• Organs: specialized structure with a specific function

• Organ System: group of organs that carry out body functions


Body Types• colonial organism: cells

connected in a group but do not depend on each other for survival

• multicellular organism: most begin as a single cell; as the organism grows, the cells differentiate into specialized cells


Cell Diversity

• Different organelles and features allow cells to function in a variety of unique ways

• EX: muscle cells have a lot of mitochondria (for energy)


Eukaryotic Animal Cell


Inside the Eukaryotic Cell• cytoskeleton: helps the cell

move, keep its shape, and organize its parts

• nucleus: surrounded by a double membrane called the nuclear envelope; stores genetic information

• ribosomes: make proteins

• Golgi Apparatus: modifies, sorts, and packages proteins for transport

• vesicle: sac formed by a membrane

• lysosome: vesicle with enzymes to break down large molecules

• Smooth ER: no ribosomes; makes lipids and breaks down toxic substances

• Rough ER: ribosomes attached; prepares proteins for transport out of cell

• Mitochondria: uses energy from organic compounds to make ATP; has own DNA


Cell Membrane• cells maintain homeostasis

by controlling the movement of substances across the cell membrane

• A lipid bilayer forms the cell membrane

• polar head

• non-polar tail


Eukaryotic Plant Cell


Inside a Plant Cell• central vacuole: holds

water; helps a plant stand upright

• chloroplast: uses light to make sugar from CO2 and water (photosynthesis)

• Also has:

• mitochondria

• nucleus

• vesicle

• Rough ER

• Smooth ER

• Golgi Apparatus


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