Biology
shanice1
IntrotoCellBiology1.pptx
Cell Biology
Enzymes and Intro to Cell Biology
Guided Meditation
Learning Outcomes for part 1
Exam #1 Reflection: What went well? What needs improvement? (ie. time limitation, preparedness, form study groups)
Students will know major ‘hidden figures’ in science and their contributions
Students will understand the structure and functions of enzymes
Reflect on Exam #1
What are two specific things that went well during or in preparation for Exam #1?
What is one thing that needed improvement for Exam #1?
Take a moment to think to yourself and be prepared to share out!
Today we honor...
Gladys West (1930 – present)
American mathematician known for her work contributing to the development of the Global Positioning System
Gladys West
Macromolecules are polymers, built from monomers
A polymer is a long molecule consisting of many similar building blocks
These small building-block molecules are called monomers
Three of the four classes of life’s organic molecules are polymers:
Carbohydrates
Proteins
Nucleic acids
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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A dehydration reaction occurs when two monomers bond together through the loss of a water molecule
Enzymes are macromolecules that speed up the dehydration process
Polymers are disassembled to monomers by hydrolysis, a reaction that is essentially the reverse of the dehydration reaction
The Synthesis and Breakdown of Polymers
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
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Fig. 5-2a
Dehydration removes a water
molecule, forming a new bond
Short polymer
Unlinked monomer
Longer polymer
Dehydration reaction in the synthesis of a polymer
HO
HO
HO
H2O
H
H
H
4
3
2
1
1
2
3
(a)
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Figure 5.2 The synthesis and breakdown of polymers
Fig. 5-2b
Hydrolysis adds a water
molecule, breaking a bond
Hydrolysis of a polymer
HO
HO
HO
H2O
H
H
H
3
2
1
1
2
3
4
(b)
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Figure 5.2 The synthesis and breakdown of polymers
Enzymes (a special kind of protein)
A special kind of protein that helps a chemical reaction to occur is called a catalyst, and the molecules that catalyze biochemical reactions are enzymes!
Enzymes made by cells make all of these reactions possible
Enzymes are catalysts!
All are unique enzymes
Most names end with “-ase”
Break down our food into subunits
Build all our proteins
Break down glucose to release energy
Convert extra food into fat
Basically, they do everything, but each enzyme catalyzes only ONE reaction!!
Turn and talk
1. What subunits make up an enzyme? 2. What would happen if there was no enzyme? 3. If the 3D shape of the enzyme was changed, what would happen?
Learning Outcomes for part 2
Describe the role of cells
Compare and contrast light microscope and electron microscope and understand the parts of a general microscope
Compare and contrast prokaryotic cells and eukaryotic cells
Describe the structure of eukaryotic plant and animal cells
Explain the role of the plasma membrane
Summarize the functions of the major cell organelles
Describe the cytoskeleton and extracellular matrix
The basic units of life!
Introduction to Cells
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Sample Footer Text
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In 1951, Henrietta went to The Johns Hopkins Hospital complaining of vaginal bleeding
She was diagnosed with cervical cancer and her cells were collected and sent to a lab
Her cells were the only cells that did not die and continue to grow
Today, HeLa cells are used to study the effects of hormones, toxins, viruses, growth of cancer cells without experimenting on humans.
HeLa Cells
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https://www.youtube.com/watch?v=AENPGhVWBvE&t=14s
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Family settled for undisclosed amount in Aug. 2023
This OpenStax ancillary resource is © Rice University under a CC-BY 4.0 International license; it may be reproduced or modified but must be attributed to OpenStax, Rice University and any changes must be noted. Any images credited to other sources are similarly available for reproduction, but must be attributed to their sources.
(a) Nasal sinus cells (viewed with a light microscope), (b) onion cells (viewed with a light microscope), and (c) Vibrio tasmaniensis bacterial cells (viewed using a scanning electron microscope) are from very different organism, yet all share certain characteristics of basic cell structure. (credit a: modification of work by Ed Uthman, MD; credit b: modification of work by Umberto Salvagnin; credit c: modification of work by Anthony D'Onofrio; scale-bar data from Matt Russell)
Figure 3.1
Your body has many kinds of cells, each specialized for a specific purpose. Just as a home is made from a variety of building materials, the human body is constructed from many cell types. For example, epithelial cells protect the surface of the body and cover the organs and body cavities within. Bone cells help to support and protect the body. Cells of the immune system fight invading bacteria. Additionally, red blood cells carry oxygen throughout the body. Each of these cell types plays a vital role during the growth, development, and day-to-day maintenance of the body. In spite of their enormous variety, however, all cells share certain fundamental characteristics.
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Observation of Cells
van Leeuwenhoek observing protozoans
Hooke observing cork
1660’s
These two scientists provide observations that helped us to better understand cells of living organisms and the organelles within them.
Antonie van Leeuwenhoek, sometimes called “the Father of Microbiology,” is typically credited as the first person to have created microscopes powerful enough to view microbes. Van Leeuwenhoek began his career selling fabrics. However, he later became interested in lens making (perhaps to look at threads) and his innovative techniques produced microscopes that allowed him to observe microorganisms as no one had before
Hooke was looking at everything with his new microscope!!
Robert Hooke used his (a-left graphic) compound microscope to view (b-right graphic) cork cells. Both of these engravings are from his seminal work Micrographia, published in 1665.
Laid the foundation of cell biology. Without their work with one of the first microscopes (which has been enhanced since then),cell biology would not be as advanced as it is now. Reading such old articles will hopefully provide an appreciation for how far science has come and gain an appreciation for the scientists’ shoulders who we stand upon.
Microscopes
Light vs. Electron Microscopes
Salmonella seen through a light microscope
Salmonella seen invading human cell with an electron microscope
Salmonella seen through a light microscope
Salmonella seen invading human cell with an electron microscope
In contrast to light microscopes, electron microscopes use a beam of electrons instead of a beam of light. Not only does this allow for higher magnification and, thus, more detail, it also provides higher resolving power. Preparation of a specimen for viewing under an electron microscope will kill it; therefore, live cells cannot be viewed using this type of microscopy. In addition, the electron beam moves best in a vacuum, making it impossible to view living materials.
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Characteristics of All Cells
A surrounding membrane
Protoplasm – cell contents in thick fluid
Organelles – ‘little organs’ within cells- structures for cell function
Control center with DNA
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NOT drawn to scale!!
All cells share four common components: 1) a plasma membrane, an outer covering that separates the cell’s interior from its surrounding environment; 2) cytoplasm, consisting of a jelly-like region within the cell in which other cellular components are found; 3) DNA, the genetic material of the cell; and 4) ribosomes, particles that synthesize proteins. However, prokaryotes differ from eukaryotic cells in several ways.
A prokaryotic cell is a simple, single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle
A eukaryotic cell is a cell that has a membrane-bound nucleus and other membrane-bound compartments or sacs, called organelles, which have specialized functions. The word eukaryotic means “true kernel” or “true nucleus,” alluding to the presence of the membrane-bound nucleus in these cells.
At this point, it should be clear that eukaryotic cells have a more complex structure than do prokaryotic cells. Organelles allow for various functions to occur in the cell at the same time.
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Prokaryotic VS. Eukaryotic
Prokaryotic Organisms:
-E. Coli bacteria
-Cyanobacteria
-Streptococcus
-Archaea
Eukaryotic Organisms:
-plants
-animals
-fungi
-protists
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Prokaryotic Cells
First cell type on earth
Bacteria and Archaea (photosynthetic)
This Photo by Unknown Author is licensed under CC BY
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A prokaryotic cell is a simple, single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle
Eukaryotic Cells
Nucleus bound by membrane
Include fungi, protists, plant, and animal cells
Possess many organelles
Protozoan
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Review all of the cell pats listed in the text (Table 3.1)
Point out organelles that are found in animal cells that are not found in plant cells.
Organelles
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Organelles= little organs within the eukaryotic cell that perform specific functions to ensure the cell’s survival
Cellular machinery
Exit Slip: Tap In
Compare and contrast prokaryotic cells and eukaryotic cells. How are they different and how are they similar?
Compare and contrast plant cells with animal cells. How are the different and how are they similar?
Learning Outcomes for part 3
Describe the role of cells
Compare and contrast light microscope and electron microscope and understand the parts of a general microscope
Compare and contrast prokaryotic cells and eukaryotic cells
Describe the structure of eukaryotic plant and animal cells
Explain the role of the plasma membrane
Summarize the functions of the major cell organelles
Describe the cytoskeleton and extracellular matrix
Cell Walls
Found in plants, fungi, and many protists
Surrounds plasma membrane
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Cytoplasm
Viscous fluid containing organelles
components of cytoplasm
Interconnected filaments & fibers
Fluid = cytosol
Organelles (not nucleus)
storage substances
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Cytoskeleton
Filaments & fibers
Made of 3 fiber types
Microfilaments
Microtubules
Intermediate filaments
3 functions:
mechanical support
anchor organelles
help move substances
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Nucleus
Control center of cell
Double membrane
Contains
Chromosomes
Nucleolus
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DNA
Hereditary material
Chromosomes
DNA
Proteins
Form for cell division
Chromatin
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Endoplasmic Reticulum
Helps move substances within cells
Helps synthesize lipids and proteins
Network of interconnected membranes
Two types
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
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Golgi Apparatus
Involved in synthesis of plant cell wall
Packaging & shipping station of cell
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The Golgi processes proteins made by the endoplasmic reticulum (ER) before sending them out to the cell. Proteins enter the Golgi on the side facing the ER (cis side), and exit on the opposite side of the stack, facing the plasma membrane of the cell (trans side). Proteins must make their way through the stack of intervening cisternae and along the way become modified and packaged for transport to various locations within the cell. The Golgi apparatus cisternae vary in number, shape, and organization in different cell types.
Each cisterna or region of the Golgi contains different protein modification enzymes. What do these enzymes do? The Golgi enzymes catalyze the addition or removal of sugars from cargo proteins (glycosylation), the addition of sulfate groups (sulfation), and the addition of phosphate groups (phosphorylation).
Bacteria-Like Organelles
Release & store energy
Types
Mitochondria
(release energy)
Chloroplasts
(store energy)
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Mitochondria
Have their own DNA
Bound by double membrane
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Mitochondria
Break down fuel molecules (cellular respiration)
Glucose
Fatty acids
Release energy
ATP (energy source for cell)
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Chloroplasts
Derived form photosynthetic bacteria
Solar energy capturing organelle
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Photosynthesis
Takes place in the chloroplast
Makes cellular food – glucose
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How does the extensive surface area (structure) of chloroplasts and mitochondria relate to their function?
The folding of the inner membranes of both the chloroplasts and mitochondria increases the surface area inside the organelles. Since many of the chemical reactions happen on the inner membrane, the increased surface area creates more space for reactions to occur. If you have more space to work, you can get more work done. Similar surface area strategies are used by microvilli in your intestines.
Questions???
