Cell Structure and Function

The Cell The cell is the smallest unit of life that can carry out life processes.

Discoveries Leading to The Cell Theory Robert Hooke – 1665 -observed cork through a light microscope. Anton Van Leewenhoek – 1675 -observed LIVING cells. Matthias Schleiden – 1883 –plants are made of cells. Theodor Schwann – 1839 –animals are made of cells

The Cell Theory The cell theory states that: all living organisms are made of one or more cells, cells are the basic units of structure and function, cells come only from pre-existing cells.

Prokaryotic Cell Prokaryotic-cells that do not have a nucleus and internal membrane-bound structures Most unicellular organisms are prokaryotes. Bacteria

Eukaryotic Cell Eukaryotic-Cells that do have a nucleus and internal membrane-bound structures. Most multicellular organisms are eukaryotes. Yeast and algae (unicellular, eukaryotes) Plant and animal

Features Common to Cells: Cytoplasm – Gel like material that protects, supports and suspends organelles.

Features Common to Cells: Cell membrane – Flexible, semi-permeable membrane that allows some materials in and keeps others out. This helps to maintain cellular homeostasis.

Nucleus “Command center” Surrounded by a nuclear envelope Contains genetic material: chromatin chromosomes

Chloroplast – green pigments of plant cells Examples: Chloroplast – Located in plant cells, some bacteria, and protists. Capture light energy to produce and store food Contain chlorophyll-green pigment that traps light energy

Cell wall Rigid outer covering PLANT CELLS Located outside the cell membrane Provides support and protection

Animal Cell Plant Cell

Parts of the Cell

Features Common to Cells: Cytoskeleton – tiny fibers that give structure and support to the cell.

Ribosomes site where proteins are made Can be found floating in the cytoplasm or attached to endoplasmic reticulum

Rough Endoplasmic Reticulum (RER) Series of folded membranes allow a large amount of work to be done in a small amount of space Transportation unit for the cell Rough Endoplasmic Reticulum (RER) Ribosomes attached Protein synthesis

Smooth Endoplasmic Reticulum Series of folded membranes allow a large amount of work to be done in a small amount of space Transportation unit for the cell Smooth Endoplasmic Reticulum (SER) Produce and store lipids

Golgi Apparatus Vesicles Flattened tubular membranes Packaging plant Modify, sort, package, and transport proteins throughout the cell

VACUOLES Storage sacs Temporary storage of materials Store food, enzymes, waste Plant cells have one large vacuole. Animal cells have many small vesicles.

LYSOSOMES Contain digestive enzymes Digest excess or worn organelles, food particles, viruses, and bacteria Surrounded by membrane that prevents it from destroying the cell Can burst causing cell death

Mitochondria Chapter 4 Cellular respiration -converts food into energy Cell “Powerhouse” Number of mitochondria depends upon the function of the cell Ex: muscles cells have more mitochondria than fat cells

Centriole Help with cell reproduction Only found in animal cells

Cilia and Flagella Flagella-long, whip-like projections Aid in movement and feeding Composed of microtubules Cilia-short, numerous hair-like projections that move in a wavelike motion

Plant cell vs. Animal Cell

Plant vs Animal cells Animal Cell vs. Plant cell Animal Cell DO contain centrioles. DO NOT contain a cell wall or plastids. Plant Cell DO contain a cell wall, plastids, and a large central vacuole. DO NOT contain centrioles