Chapter 6 A Tour of the Cell -...
Transcript of Chapter 6 A Tour of the Cell -...
Biology – Kevin Dees
Chapter 6A Tour of the Cell
Biology – Kevin Dees
• The cell is the ______ _____ of _____
• Although cells differ substantially from one another, they all share certain characteristics that reflect a common ancestry and remind us of the unifying theme of evolution
• Three main parts of a cell– Plasma membrane– Cytoplasm– Genetic control
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History of the cell• First ‘microscopes’ – 1590 • ________ _______
– coined the term “cell” in 1665
• Little knowledge was gained about cell structure –function until the 1950’s– WHY??
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Microscopes• Essential tool for studying the cell
– Light microscopes – Electron microscopes – much higher
magnification and resolution • Electron microscopes made the detailed
study of cell ultrastructure possible
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Comparison of Light , Transmission electron and Scanning Electron microscopy
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Recall, that there are two basic categories of cells:
• ___________ cells –– Without a true nucleus – organisms in the Domain Archaea and
Bacteria
• ____________ cells-– With a true membrane bound nucleus– plants, animals, fungi, etc..
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Prokaryotic cells
• Very simple – contain:– Plasma membrane– Cytoplasm– Genetic control
• No nucleus –prokaryotic chromosome is not enclosed in a membrane!!!!!
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Eukaryotic cells
• True nucleus – genetic material is surrounded by membrane.
• Typically larger than prokaryotic cells but still small
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• Why are cells small?
• Large living things typically do not have larger cells? Why??
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Plasma membrane
• Forms a selective barrier to allow the controlled passage of materials in and out of the cell
• General construction– ___________________ _________ and ___________
• Forms the surface area of a cell
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Surface area regulates cell size• Materials must pass in-out of cell.• Must pass through plasma
membrane• Smaller objects tend to have a higher
ratio of surface area to volume
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Comparison of typical animal and plant cells
• Recall the three components that all share have in common:1. _____________2. _____________3. _____________
• We are going to survey generalized animal and plant cells– Look for similarities and differences between
the two
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General Animal cell
A
B
C
D
E
F
G
H
I
J
KL
M
N
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General Plant cell
A
B
C
D
E F
G
H
IJ
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• Nuclear envelope– Nuclear pores– Function- ________________________________________
• Nucleolus– Function- __________________________________________
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Genetic material in nucleus• Genetic material- DNA and some proteins
– When cell is functioning normally, it is the form of ______________________________
– When cell is preparing to divide, it is in the form of ______________________________
– Somatic cells are ________________________________
– Gametes are ___________________________________
– Humans – 23 pair of chromosomes in somatic cells– 23 single chromosomes in gametes
• Why??????
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Ribosomes
• Function of a ribosome ____________________________
• Structure of a ribosome– Not surrounded by a membrane– Made of RNA and Proteins– Large and small subunits
• Location– Bound ribosomes – attached to ________________________– Free ribosomes – found in ____________________________
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Main parts• Nuclear envelope• Rough Endoplasmic
reticulum• Smooth endoplasmic
reticulum• Golgi complex• Vesicles
Endomembrane system
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• __________________– Synthesis of lipids, steroids,
phospholipids– Detoxification
• ___________________– Important in protein synthesis– produces more ‘membrane’ for
the cell
• __________________– Products refined, stored,
sorted, shipped
• _________________– Used for transport
Endomembrane system
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• The cis face is located ______________the ER– Transport vesicles from the ER move materials to the Golgi
• The trans face is located ______________ the ER – Gives rise to vesicles which move away from the Golgi
Golgi apparatus
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• ________________ Membranous sacs of hydrolytic enzymes for intracellular digestion
• (a) ____________creation of food vacuole and subsequent digestion
• (b) ______________ recycles cellular components
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• Vacuoles - function =______________________
– Food vacuoles
– __________ vacuole found only in plant cells
• _______________ membrane that surrounds central vacuole
• Turgor pressure – water– Storage of electrolytes
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• Mitochondrion (sing) mitochondria (plural)
– Free ribosomes and mitochondrial DNA
– Site of _____________________________
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• Chloroplasts – Found in ____________ cells
• Site of ____________________
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__________________________Functions for support, motility and
regulation
• ___________– Pair of centrioles– Creation of the
mitotic spindle used during cellular division
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• Cilia
• Flagella
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Cell wall of plants• Composed of ____________• Structure for plant cell
• ____________________– Connections between plant
cells
• _________________– joins adjacent plant cells
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Cellular junctions• Plant cells
– Plasmodesmata• Animal cells
– Tight junctions• Continuous seal
– Gap junctions• Communication
between cells– Desmosomes
• ‘rivets’
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All activities of cells must be coordinated
• The ability of the macrophage to recognize the harmful bacteria, locate them, capture them, and engulf them to be destroyed takes a coordinated effort