Upload
denis-newton
View
225
Download
5
Tags:
Embed Size (px)
Citation preview
CHAPTER 7 -2
Eukaryotic Cell Structure
Basic Cell Info
Cells are like factories Every part inside the cell has a specific job
Each part of a cell functions like a little organ Little organ = Organelle
Cells are divided into 2 parts Nucleus Cytoplasm
Cytoplasm is the jelly-like interior PLUS all the organelles outside the nucleus
Eukaryotic Cell Organelles
Plant and Animal: Cell membrane Nucleus Nucleolus Nuclear envelope Ribosomes Rough Endoplasmic Reticulum Smooth Endoplasmic
Reticulum Golgi Bodies (Apparatus) Lysosomes Mitochondria Vacuoles
Cytoskeleton
Animal Cells: Centrioles Many small vacuoles
Plant Cells: Cell walls Chloroplasts One central water Vacuole
Eukaryotic Animal Cell
Eukaryotic Plant Cell
Nucleus
Nucleus: control center of the cell
• houses chromatin • DNA bound to Proteins• Code for proteins and
molecules) Nuclear Envelope: a porous
membrane that surrounds the nucleus• Protects DNA from damage• Allows only specific
molecules in or out Nucleolus : A special, dense
location inside the nucleus• Site of ribosome formation
Ribosomes
Protein MachinesMade of ribosomal RNA
(rRNA) and proteinFound free floating and
attached to Rough Endoplasmic Reticulum
Attaches amino acids (Protein monomers) together into a chain (polypeptide) Uses messenger RNA
(mRNA) and transfer RNA (tRNA)
Rough Endoplasmic Reticulum
An extensive network of membrane-bound tubules surrounding the nucleus
Shapes proteins as they are being formed by ribosomes The attached ribosomes
“feed” the forming protein into the RER through pores
Called “Rough” ER because of the rough appearance ribosomes give it under a microscope
Smooth Endoplasmic Reticulum
An extension of RERDoes NOT have
ribosomes covering itHelps make fats
(lipids) and cholesterols This is where
components of the cell membrane are initially formed as well as membranes for other organelles
Golgi Bodies (Apparatus)
Look like stacks of flattened pancakes
Made of pinched-off pieces of RER containing folded/shaped proteins
Packaging/Shipping department of cell Similar to a post office,
this organelle sends the proteins to their final destination (either cell membrane or out of the cell)
Lysosomes
Janitors of the cellContain lots of
enzymes and have a pH of about 5 (acidic)
Break down old organelles and metabolic wastes before they harm the cell
Vacuoles
Storage Closets of cell Store food, water, waste Plant cells have one large,
central water vacuole Allows the plant to support
heavy structures such as leaves Animal cells can have many
small vacuoles for food and water
Some single-celled organisms have special vacuoles called contractile vacuoles These pump out excess water
by contracting in order to maintain homeostasis
Plant Cell: Central Vacuole
Mitochondria
Powerhouse of the cellDouble-membrane
organelleCreates energy in the form
of adenosine triphosphate (ATP)
Site of Aerobic Respiration! In other words, this is where
sugar is broken down with oxygen to make energy (ATP)
Cells that need LOTS of energy have LOTS of mitochondria EX: muscle cells, brain cells
Has its own DNA
Plant Cell Exclusive: Chloroplast
Double-membrane organelles
Site of photosynthesis
Contain the green pigment chlorophyll (a protein)
Builds sugar (glucose) molecules from Water, Co2, in the presence of sunlight
Has its own DNA
Cytoskeleton
Internal network of protein filaments and tubules
Provide: Shape and support Pathways for molecules
and organelles to move Ex: Golgi bodies send
proteins out along microtubules
Movement of cell parts Ex: cilia, microvilli,
flagella
Animal Cell Exclusive: Centrioles
Aide in cell divisionMade of
microtubulesForm spindle fibers
and astral rays during mitosis and meiosis (More to come in
chapters 10 and 11)
Cell Membrane
The bouncerDecides what goes in
and out of the cellControls cellular
transport based on molecule size AND special transport proteins that are specific for moving certain molecules across the membrane
Made MOSTLY of lipids, contains SOME proteins
Plant Cell Exclusive: Cell Wall
Give the plant cell rigidity and support
Made of cellulose Plant starch
Prevents the plant cell from exploding when water pressure (osmotic pressure) is too high in the cell
Important Points!
Plant and animal cells are Eukaryotic!Prokaryotic cells contain SOME but not all
of the structures reviewed in this power point
Bacteria (Prokaryotes) have NO nucleus, but they MIGHT have a cell wall
Fungi (Eukaryotes) have NO chloroplast, but do have a nucleus and cell wall Fungi are NOT plants!