Cell Structures and Functions
Cell Structure and Function
Sec. 7-1
There are 2 basic types of cells: prokaryotic and eukaryotic.
Prokaryotic cells have genetic material not contained within a nucleus….known as BACTERIA
Eukaryotic cells contain a nucleus in which genetic material is contained.
Sec. 7-2
Eukaryotic cell structure
Cytoplasm: inside cell membrane contains organelles
Organelles: cell parts
Nucleus: contains DNA
Nuclear envelope: encloses nucleus
Chromatin: DNA bound to proteins, granular
Chromosomes: condensed chromatin ready for
cell division
Nucleolus: assembly of ribosomes
Ribosomes: build proteins, found in cytoplasm
Endoplasmic reticulum: site of assembly for proteins and
lipids for export
rough ER-packaging, synthesis/transport of proteins
smooth ER-contain enzymes that perform specialized
tasks, involved in synthesis/transport of lipids and carbs
Golgi Apparatus: modify, sort, package proteins and other materials for storage within the cell or secretion
Lysosomes: contain enzymes, function to break down lipids, carbs, proteins for use in the cell and remove waste
Vacuoles: storage place, larger in plants than animals, contractile vacuole in some organisms regulates water
Mitochondria: double membrane organelle converts chemical energy in food to compounds more easily used by the cell, all are inherited from Mother
Chloroplasts: double membrane organelle converts sun’s energy into chemical energy
Organelle DNA: found in both mitochondria and chloroplasts….theory is they were prokaryotes that entered eukaryotic cells and developed a symbiotic relationship
Cytoskeleton: network of protein fibers that help cell maintain shape and is involved in movement…microtubules and microfilaments are principle proteins…..centrioles are made of microtubules and found only in animals cells….help organize cell division
Cell Boundries
Sec. 7-3
All cells have cell membranes that regulate what goes in and out of the cell.
They are composed of a lipid bilayer with proteins and carbohydrates embedded that have different functions.
Plants and many prokaryotes have cell walls that provide structure and support. The cell wall is made of different kinds of carbohydrates. (example…cellulose…..wood)
Some substances can diffuse across cell membranes without the use of energy.
Diffusion of water across a selectively permeable membrane is known as osmosis.
Different concentrations of solutes have very different effects on cells.
Facilitated Diffusion uses special proteins embedded in the cell membrane that allow big molecules like glucose to pass through.
Active Transport uses energy and special protein pumps to move substances across the cell membrane.
Endocytosis and exocytosis moves larger clumps of materials using energy.
The Diversity of Cellular Life
Sec. 7-4
Unicellular organisms can grow, respond, reproduce and transform energy.
Multicellular organisms have cells that specialize for certain tasks.
Red blood cells have special proteins that carry oxygen.
Pancreas is made of cells that are specialized to make enzymes (proteins) therefore they have lots of ribosomes and endoplasmic reticulum along with Golgi apparatus and vacuoles. Why????
Muscle cells have cytoskeletons that help with movement of cells.
In plant cells, guard cells and stomata regulate gas and water exchange.
DIFFERENT CELLS HELP THE ORGANISMS MAINTAIN HOMEOSTSIS.
Like cells are organized into tissues.
Like tissues are organized into organs.
Like organs are organized into organ systems.