Cells Biology

How many cells do we have? There are approximately 1x1014 cells in the human body… 1,000,000,000,000,000 Oh, that’s about 100 trillion!

Cell Theory All living things are composed of one or more cells. The cell is the smallest entity that retains the properties of life. New cells arise only from cells that already exist.

Organelles Organelles = specialized subunit within a cell that has a specific function, and is usually separately enclosed Like organs in our bodies, cells have organelles.

Animal Cell Cytoplasm Ribosomes Cell Membrane Vacuole Nucleus Mitochondria Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Vacuole Golgi Complex

Cell Membrane/ Plasma Membrane Nickname: “The gatekeeper” Function: separates the inside of the cell from the external environment controls the flow material into and out of the cell

Cell Membrane/ Plasma Membrane The cell membrane allows only some substances to pass through it. Therefore, it is called a “semi-permeable” membrane.

Cytoplasm a thick liquid residing between the cell membrane holding all organelles

Cytoskeleton Nickname: “The Skeleton” Function: cellular "scaffolding" or "skeleton" contained within the cytoplasm and is made out of protein Gives the cell structure and shape Act as rail road tracks for moving things around

Cytoskeleton Microtubules Actin Filaments

Nucleus Nickname: “The Control Center” or “Brain” Function: Controls all cell activities Holds the DNA (genetic material) Regulates gene expression

Mitochondria Nickname: “The Power House” Function: Produces energy to power cell activities

Ribosomes Nickname: “Protein Factory” Function: Make proteins

Endoplasmic Reticulum (ER) Nickname: “Roads” Function: Internal delivery system of the cell Made up of channels that transport material made in the cell from one place to another

2 Types of Endoplasmic Reticulum Smooth Endoplasmic Reticulum (SER) No ribosomes attached Makes fats or lipids Rough Endoplasmic Reticulum (RER) Has ribosomes attached Helps make proteins Products of the ER become enclosed in vesicles and travel to the golgi apparatus

Golgi Apparatus Nickname: “The Shippers” Function: Sorts products from the ER and packages them into vesicles packages, modifies, and transports materials to different location inside/outside of the cell

Vesicles Nickname: “Delivery Person” Function: small membranous spheres that transport materials around cell

Lysosomes Nickname: “Clean Up Crew” Function: Contain proteins (enzymes) that break down food into smaller particles that the rest of the cell can use Destroy old cells, recycle the parts Destroy invaders

Lysosomes Fuses with other vesicles to digest nutrients brought into the cell or destroy dangerous microorganisms.

Centrioles Nickname: “Spiderman” Function: Protein tubes that play a role in cell division Shoot out spindle fibers that guide chromosomes during cell division

Plant Cells Central Vacuole Chloroplasts Cell Membrane Cell Wall Section 7-2 Central Vacuole Chloroplasts Cell Membrane Cell Wall Go to Section:

Plant Cells Cytoplasm Central Vacuole Smooth ER Ribosomes Chloroplasts Cell Membrane Cell Wall Nucleolus Golgi Bodies Nucleus Mitochondria Rough ER

Cell Wall Function: provides support and protection to the cell membrane Location: Outside the cell membrane in plant cells

Chloroplast (a type of Plastid) Nickname: “Powerhouse of Plants” Function: Traps energy from the sun to produce food for the plant cells (photosynthesis) Contains chlorophyll = the green pigment that begins the process of photosynthesis

Chloroplast

Chloroplasts Under a Microscope

Central Vacuole Function: Store water Vacuoles play a role in turgor pressure When a plant is well-watered, water collects in cell vacuoles producing rigidity in the plant Without sufficient water, pressure in the vacuole is reduced and the plant wilts

Comparing Plant and Animal Cells Plasma membrane Nucleus Mitochondria Ribosomes Golgi Endoplasmic Reticulum Cytoplasm Cytoskeleton Small vacuoles Centrioles Lysosomes Cell wall Plastids Chloroplasts Central Vacuole