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C7 Cell Structure & Function
C7 Cell Structure and Function
Cell theory states:
1. All living things are made of cells.
2. Cells are the basic units of structure and function in living
things.
3. New cells are produced from existing cells.
Microscopes:
1. Light microscope – magnifies up to 1,500 X using light.
2. Electron microscope – magnifies up to about 1,500,000 X
uses electrons
Prokaryotes – very small cells without a nucleus. Only example:
bacteria.
Eukaryotes – larger, more complex cells with one or more nuclei.
ex. all other cells except for bacteria.
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C7 Cell Structure & Function
Nucleus – (plural, nuclei) large membrane-enclosed structure
containing DNA.
The DNA appears granular most of the time and is called chromatin.
When the cell is dividing the chromatin condenses to form
chromosomes.
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C7 Cell Structure & Function
Nuclear envelope – double membrane with pores surrounding
nucleus.
Nucleolus – dense region of the nucleus where ribosomes are made.
Organelles – membrane bound structure in eukaryotes that carries
out some function for the cell, ex. nucleus, mitochondria
Cytoplasm – gel-like substance outside the nucleus.
Ribosomes – small particles of RNA and protein where proteins are
made in the cell.
Endoplasmic reticulum (ER) – site where lipids and proteins are
assembled. These materials are exported from the cell or become
part of cell membrane.
Rough ER – has ribosomes and makes proteins.
Smooth ER – has no ribosomes and makes lipids or detoxifies.
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C7 Cell Structure & Function
Golgi apparatus – modifies, sorts, and packages proteins and other
materials for storage in the cell or secretion from the cell.
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C7 Cell Structure & Function
Lysosomes – enzyme filled organelles that digest food for the cell
and get rid of old organelles.
Vacuoles – store materials like water or nutrients.
Mitochondria – help convert food energy into cellular energy.
Chloroplasts – in plants and some Protists, capture energy from
sunlight and convert it into chemical energy (photosynthesis).
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C7 Cell Structure & Function
Cytoskeleton – network of protein filaments that maintain the cell’s
shape and aid in movement.
Centrioles – help organize cell division, (not found in plants).
Cilia – short projections made from the microtubules that function in
movement.
Flagella – long projections from the microtubules that aid in
movement.
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C7 Cell Structure & Function
Cell wall – provides support & protection in bacteria, plants, fungi,
and some Protists. Made of cellulose in plants. NOT in animal cells.
Cell membrane (Plasma membrane) – regulates what enters and
leaves the cell and also provides protection and support. Found in
ALL cells. Made of phospholipids.
Unicellular organisms – when one cell is the organism, ex. Bacteria
and many Protists.
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C7 Cell Structure & Function
Multicellular organisms have many cells that are specialized.
Cell differentiation or cell specialization - when cells develop in
alternative ways to perform different tasks, “Go Go Stem Cells” ex.
Red blood cells are specialized to transport oxygen. Pancreatic cells
produce certain proteins. Guard cells in plants open and close the
stomata.(link to stem cell animation)
Cell –collection of living matter enclosed by a barrier; basic unit of
life.
Tissues – group of similar cells that perform a particular function.
Organ – many groups of tissues work together to function as an
organ.
Organ system – a group of organs that work together to perform a
specific function, like digestion.
Diffusion through cell membranes:
Diffusion – movement of particles from an area of higher
concentration to lower concentration. (Requires NO energy).
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C7 Cell Structure & Function
Concentration – mass/volume.
Osmosis – the diffusion of water through a selectively permeable
membrane.
Isotonic – concentrations are the same on both sides of the
membrane.
Hypertonic – more concentrated.
Hypotonic – less concentrated.
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C7 Cell Structure & Function
Facilitated diffusion – diffusion through protein channels without
using energy.
Active Transport – movement of particles that takes energy.
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C7 Cell Structure & Function
Passive Transport – movement of particles without using energy.
Endocytosis – taking material into a cell by engulfment, (takes
energy).
Phagocytosis – taking in food or solid particles.
Exocytosis – releasing material from a cell, (takes energy).
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