1. “We, all of us, are what happens when a primordial mixture of hydrogen and helium evolves for so long that it begin to ask where it came from”
-Jill Tarter
Life’s home: The Cell
Chapter 4

2. Cell Theory All living organisms are composed of cells
Unicellular or multicellular
Cells come from ________ cells
Modern additions to the theory
All cells use energy and have a metabolism
All cells have similar chemical composition
All cells have genetic information in the form of DNA

3. Cells are Specialized Over _____ different cells in the human body
You are made of trillions of cells!!
Reproductive cells
Red blood cell
Cardiac muscle cells
Bone cells
Nerve cell

4. Why so small? __________________________!
Greater surface area means greater ________
Transporting stuff into and out of the cell

5. Two Main Groups of Cells
Prokaryotic
(Bacteria and Archaea)
Eukaryotic
(Protists, Plants, Animals and Fungi)
*Not to scale

6. Prokaryotic and Eukaryotic Cells
Prokaryotic cell

7. Size of Prokaryotic Cells

8. Domains of Life Bacteria Archaea Eukarya Unicellular prokaryotes
Extremophiles
Eukarya
Unicellular and __________ eukaryotes
Protists
Fungi
Plants
Animals

10. Domain: Bacteria Prokaryotic cells
No membrane bound nucleus or organelles
Single-celled organisms
Asexual reproduction
____________ in cell wall separates bacteria from archaea

11. Domain: Archaea
Prokaryotic cell but similar to Eukaryotes in DNA replication and protein synthesis
More closely related to _____________
________________: organisms that live grow best in one or more conditions that would kill most organisms
Thermophiles: live in extremely ___ environments
Halophiles: live in extremely ______ environments
Methanogens: Methane releasing archaea that are poisoned by _________

12. A Borrowed Life
Virus: an infections particle incapable of replicating outside of a cell, which consists of an RNA or DNA genome enclosed in a protein coat (capsid)
__________________ parasites
Arguments for describing viruses as non-living
Can not __________ outside of host cell
Can not carry out _________________ outside of outside of host cell
Lack ribosomes and enzymes
HIV attacking a white blood cell

13. Prokaryotic Cells
Pili: attachment structures on the surface of some prokaryotes
________: location of cell’s DNA (not enclosed in a membrane)
Ribosomes: site of protein synthesis
Cell wall: rigid structure outside of cell membrane
Bacterial
chromosome
__________: sticky outer coating on many prokaryotes
A typical
rod-shaped
bacterium
Flagella: locomotion organelles in some bacteria
A thin section through the
bacterium Bacillus coagulans

14. Eukaryotic Cells

15. Prokaryotic Reproduction
________________: DNA replicates and then the cell divides into two separate cells

16. Prokaryotic and Eukaryotic Cells
Characteristics
Prokaryotic Cells
Eukaryotic Cells
Cell Size
Small (0.2 – 2.0 µm in diameter)
Large (10 – 100 µm in diameter)
Organization
Always single celled
Often ________________
Nucleus
_________________ or nucleus, Nucleoid
Membrane bound nucleus
Membrane-enclosed organelles
Absent
Present (e.g. lysosomes, Golgi complex, mitochondria)
Cytoplasm
No cytoskeleton or cytoplasmic streaming
Cytoskeleton, cytoplasmic streaming
Ribosomes
Present, smaller size
Present, larger size
Chromosomes (DNA)
Usually _____________ chromosome
__________________ chromosomes
Cell division
Binary fission
Involves mitosis
Sexual Recombination
None, transfer of DNA only
Involves meiosis

17. Check Your Understanding
True or False: All things on earth are composed of cells True or False: All organisms within the domains bacteria and archaea are made up of prokaryotic cells True or False: Viruses are considered no living because they do not have their own DNA

18. Check Your Understanding
Which of the following is not one of the characteristics of bacteria? a. Cell wall containing peptidoglycan b. Contain a membrane bound nucleus c. Asexual reproduction d. Single-cell organisms e. More than one of the above

19. Check Your Understanding
Archaea that thrive in extremely hot environments are known as ___________. a. Halophiles b. Heatophiles c. Methanogens d. Feugophiles e. Thermophiles

20. Major Components of Eukaryotic Cells
Eukaryotic cells contain organelles which allow for larger cell size through compartmentalization.
Increased efficiency
Separation of chemical reactions

21. Major Components of Eukaryotic Cells
Nucleus: membrane bound region that contains the cell’s _______
Organelles: highly organized structure in the cell that performs a specific cellular function
Cytosol: protein rich, jelly-like fluid in which the organelles are immersed
Cytoskeleton: internal supports of the cell made up of protein fibers
Plasma membrane: a complex, __________ membrane that encloses the cytoplasm and regulate passage of ions and molecules into and out of the cell
Nucleus
Other organelles
Cytosol
Cytoskeleton
Plasma membrane

22. Origin of Organelles
Autogenesis: _______ of prokaryote plasma membranes lead to compartmentalization
Endoplasmic reticulum, golgi, nuclear membrane
Endosymbiosis: one organism _________ the cell of another organism
Mitochondria, chloroplasts
Endosymbiosis
Autogenesis
Endosymbiosis

23. Origin of Organelles
Endosymbiosis: one organism lives inside the cell of another organism
Mitochondria, chloroplasts

24. Origin of Organelles
Autogenesis: infoldings of prokaryote plasma membranes lead to compartmentalization
Endoplasmic reticulum, golgi, nuclear membrane

25. The Nucleus Control center of the cell Stores DNA Nuclear membrane
Chromatin: uncoiled DNA
_______________: coiled DNA containing genes
Nuclear membrane
Contains pores
Nucleolus: region inside nucleus where ribosomal subunits in manufactured
Chromosome
DNA
Nucleus
Nucleolus
Gene

26. Endomembrane System
Rough endoplasmic reticulum: network of membranes that aid in protein processing
Studded with ___________
Smooth endoplasmic reticulum: network of membranes that functions in the synthesis lipids and ___________ of harmful molecules including alcohol, drugs and metabolic wastes.
Lacks ribosomes

27. Golgi Complex Protein processing and distribution
_______________ determine shipping route

28. Lysosomes ________ old cellular products and foreign material
Cell “digestive system”
Recycles useable molecules
Go on to form new organelles
Found in ________ cells

29. Protein Production Summary

30. Protein Production: Step 1
______________: process in which a section of DNA is copied onto messenger RNA (mRNA)
RNA polymerase
mRNA
DNA
Direction of transcription

31. Protein Production: Step 2
Translation: process by which a __________ is produced in a ribosome from information encoded within a messenger RNA

32. Mitochondria
Creates Adenosine Triphosphate (ATP) from food (cellular respiration)
ATP = cellular energy
Requires macromolecules from food and O2, expels CO2
Breakdown generates _____ (metabolic heat)

33. Cell Cytoskeleton
Aids in cell structure, cell movement and transport of materials within cell
Made up of three types of protein fibers
Microfilaments: solid, rod-like fibers that aid in cell division and changes in cell shape
Intermediate filaments: rope-like structures that give the cell strength and maintain cell shape
____________: long hollow tubes that aid in the movement of molecules and organelles throughout the cell

34. Cell Movement Modified microtubules
____: short, hair-like projections often found in large numbers on the exterior of the cell.
Used for locomotion or movement of fluid around a cell.
Flagella: long, tail-like extension used for locomotion.
Typically one per cell

35. Plant and Animal Cells

36. Check Your Understanding
Animal Cell
Both
Plant Cell

37. Plant Cells: Chloroplasts
Contain ___________, which absorbs light during photosynthesis
Likely the result of ______________
Thylakoid

38. Plant Cells: Central Vacuole
Maintains cell pressure
Stores __________
Degrades cell waste products
Large central vacuole

39. Plant Cells: Cell Wall
_________: polysaccharide that is a main structural component of cell walls
Limits water absorption
Structural strength

40. Cell Communication Plant Cells
Plasmodesmata: _________ between plant cell walls
Creates continuous cytoplasm
Do not open and close

41. Cell Communication Animal Cells
Gap junctions: protein assemblage that forms a communication channel between adjacent animal cells
____________ as needed

42. Check Your Understanding
Which of the following organelles are involved in recycling used molecules and breaking down old organelles? a. Ribosomes b. Lysosomes c. Mitochondria d. Nucleus e. Golgi apparatus

43. Check Your Understanding
Which of the following organelles are not involved in protein synthesis? a. Smooth endoplasmic reticulum b. Golgi apparatus c. Rough endoplasmic reticulum d. Nucleus e. All of the above are involved in protein synthesis

44. Check Your Understanding
Describe the different theories for the origin of organelles?