bellringer: day 01 - ms. farris' science class! · bellringer: day 01. unit 02 biochemistry,...
TRANSCRIPT
1. Make a list of everything you ate for dinner
last night. Categorize each item as either a
carbohydrate, fat or protein.
2. Which type of molecule (carbohydrate, fat or
protein) is the most important to your diet and
why?
Bellringer: Day 01
Unit 02Biochemistry,
Microscopes,
Eukaryotes vs.
Prokaryotes,
Cell Parts, and
Unicellular
Organisms
Cell Structure and
Function
▪ Organisms contain a number of large, organic molecules. We call these macromolecules.
▪ Some examples include:
▪ Carbohydrates
▪ Lipids
▪ Proteins
▪ Nucleic Acids
Macromolecules
▪Each of the four molecules we will discuss plays and important role in our body. For each,you are responsible for knowing:
▪Structure (building block)
▪Function (what does it do?)
Macromolecules
Carbohydrates
▪ Carbohydrates are composed of sugar molecules. They can be single, simple sugars or complex sugars. ▪ Building block:
monosaccharides▪ Function: Energy
storage
Carbohydrates
▪Glucose: The main source of energy for organisms. We will be talking about glucose in depth in later units.
▪Cellulose: Makes up cell walls of plants
▪Starch
▪Glycogen
Examples of Carbohydrates
Lipids
▪ Lipids are fatty compounds not soluble in water▪ Building block: glycerol
and three fatty acids▪ Function: Long term
energy storage, insulation, makeup the cell membrane
Lipids
▪Phospholipids: The lipids that make up the cell membrane. We will be discussing this in depth in a later unit.
▪Steroids
▪Fats/Oils
Examples of Lipids:
Nucleic Acids
▪ Nucleic acids are what make up genetic material in our bodies (DNA and RNA)▪ Building block:
nucleotides▪ Function: Storing and
transmitting genetic information
Nucleic Acids
▪DNA
▪RNA
Examples of Nucleic Acids
Proteins
▪ Proteins: Chains of amino acids; can be simple chains or complex folded structures
▪ Building block: Amino acids▪ Function: Storage, transport, movement,
structure, etc.
Proteins
▪Insulin
▪Hemoglobin
▪Enzymes: Speed up chemical reactions in your body
Examples of Proteins
1. List the four main macromolecules
we discussed yesterday. Choose 1
and describe its structure and
function.
Bellringer Day 02
ENZYMES
▪ Most enzymes are proteins
▪ Act as a catalyst to speed up a chemical reaction
by helping molecules react with each other faster
WHAT IS AN ENZYME?
▪ Reusable!
▪ Specific for what they catalyze (speed up)
▪ End in “-ase”
▪ Named for the reaction they help. For example…
▪ Sucrase breaks down sucrose
▪ Proteases break down proteins
▪ Lipases break down lipids
▪ DNA polymerase builds DNA
ENZYMES ARE…
▪ Lactase breaks down lactose, a common component of dairy products (like milk)
▪ People lacking the enzyme lactase are considered “lactose intolerant”-they can’t digest large amounts of milk!!
CASE STUDY: LACTOSE INTOLERANCE
▪ Re-used again for the same reaction with other molecules
▪ Very little enzyme is needed to help in many reactions!
ENZYMES ARE NOT USED UP!
Products
Substrate
Active
Site
Enzyme
▪ Remember, enzymes are
specific!
▪ Lock and Key Model: Shape of
enzyme allows substrate to fit
▪ Specific enzyme for each
specific reaction
LOCK AND KEY MODEL
Chemical Reaction
Enzyme + Substrate → Enzyme + Product
REACTANTS PRODUCTS
▪ Enzymes work by weakening bonds, which lowers
ACTIVATION ENERGY
▪ Activation Energy=energy needed for the chemical
reaction to occur (energy needed to activate!)
▪ By lowering the activation energy, the reaction can
occur faster!
SO…HOW DO ENZYMES WORK?
Reactions can occur without
the help…but not at the
speed our bodies need!
▪ Temperature
▪ High temperatures can cause enzymes to denature (unfold and lose shape), while low temperatures slow molecules down
▪ pH
▪ Changes in pH changes protein shape (most human proteins sit at a pH of 6-8)
▪ Denaturing=extreme temperature and pH can change enzyme shape, rendering it useless!
WHAT EFFECTS ENZYME ACTIVITY?
▪ Every reaction in your body is helped by an
enzyme. They are necessary for all biological
reactions!
WHY ARE ENZYMES IMPORTANT?
1. The location where reactants bind to an enzyme during a
biochemical reaction is called
a) A catalyst
b) A product
c) A substrate
d) An active site
2. How do enzymes speed up biochemical reactions?
a) They provide energy to the reactants
b) They absorb energy from the products
c) They lower the activation energy of the reaction
d) They increase the number of available reactant particles
Light Microscopes and Total Power Magnification
We can use microscopes to observe cells in greater detail Light microscopes are what we will use in class More advanced microscopes, like scanning and electron
transmission microscopes, allow us to see prokaryotic and eukaryotic cell differences in greater detail
Think about it: How does an electron microscope work? Why are these microscopes so expensive?
-A beam of electrons is scanned over a surface to create an image. They are larger, and more expensive to build and maintain!
To find this, multiply the power of the objective lens (4X, 10X, 40X), by the power of the eyepiece (usually 10X)
Think about it: A student is viewing a slide using an objective lens with a power of 4X. What is the total power magnification?
4 x 10 = 40X
Structure and Function of Living Organisms
A cell is the basic structural, functional, and biological unit of all living organisms
▪ “The building block of life”
You are made up of about 37 trillion cells!!!]
Think about it: How do a human and an elephant differ?
▪ The elephant has more cells because it is larger, but the cells themselves are not bigger!
What do we know about cells?
▪ In 1665, Robert Hooke used an early microscope to look at a thin slice of cork, a plant material.
▪ Cork looked like thousands of tiny, empty chambers.
▪ Hooke called these chambers “cells.”
▪ In 1838, Matthias Schleiden concluded that all plants were made of cells.
▪ In 1839, Theodor Schwann stated that all animals were made of cells.
▪ In 1855, Rudolph Virchow concluded that new cells were created only from division of existing cells.
▪ These discoveries led to the cell theory.
1. All living things are composed of cells. 2. Cells are the basic units of structure and
function in living things. 3. New cells are produced from existing cells.
1. What is a cell? What does cell theory tell us about cells?
2. A student is viewing a microscope with an objective lens of 40x. What is the total power magnification?
1. Are all cells the same? Why or why not?Support your answer.
Prokaryotic
▪ Simple Cells
Eukaryotic
▪ Complex Cells
▪ Plant and Animal Cells
Prokaryotic cells are smaller and less complex than eukaryotic cells▪ No membrane bound
organelles; smaller Single-celled organisms
(ex. Bacteria) Contains: Single, circular
DNA; ribosomes; cell membrane
Eukaryotic cells are larger, complex cells made up of membrane bound organelles
Each organelle within the cell carries out different roles
Eukaryotic cells make up complex organisms (mostly multicellular)…like insects, fish, and mammals like you!
PROKARYOTIC
No membrane bound organelles (no mitochondria, nucleus, vacuole, or chloroplasts)
Ribosomes One strand of circular DNA
not enclosed in a nucleus Additional circular DNA
(plasmids) can be present Smaller size
EUKARYOTIC
Contains membrane bound organelles
Ribosomes DNA (enclosed by
membrane) DNA double-helix strands Larger size
Compare and contrast prokaryotic and eukaryotic cells.
Animal vs. Plant
Animal Cell
•Nucleus•Plasma Membrane•Mitochondria•Vacuoles•Ribosome•Cytoplasm•Lysosome
Plant Cell
•Nucleus•Plasma Membrane•Mitochondria•Ribosome•Cytoplasm•Vacuole (large)•Chloroplasts•Cell Wall
The “control center” Holds the DNA Dark spot inside
nucleus is called the nucleolus (it helps makes the ribosomes)
Nucleus
The “powerhouse” of the cell
It produces most of the energy for the cell
Breaks down food to make ATP▪ ATP is major fuel for all cell
activities that require energy
Folded inner membrane increase the surface area for energy production during respiration
Mitochondria
Think about it: Which cells would need a lot of mitochondria?
Think about it: What would happen if the cell lost all of its mitochondria?
The “gate” of the cell Double membrane
structure controls what comes in and out of the cell
“YOU SHALL NOT PASS” (without permission!)
Plasma Membrane
Protein producer The ribosome makes
proteins for the cell Can be attached to
the ER or free floating in the cytoplasm
Ribosome
“Storage tanks” of the cell
It stores food, water, and chemicals in the cell
Plant cell vacuole is much larger; controls Turgor Pressure-keeps plant upright (no water=wilting)
Vacuole
Jelly/gel A liquid/gel like
substance that surrounds the organelles
Cytoplasm
The “garbage cans” Break down and digest
waste products using enzymes
Lysosome
Think about it: what would happen to the cell if all of the lysosomes burst at the same time? Does this every happen on purpose?
“Supporter/protector” The cell wall shapes
and protects the plant cell
Cell Wall
Think about it: What is the plant cell made of? (Hint: What substance do plants make during photosynthesis?)
Food producers They are green Contain green chlorophyll
and trap energy from the sun for photosynthesis
Glucose (sugar) producers Produce enough ATP to
fuel photosynthesis
Chloroplast
All these organelles work together to keep the cell running!!
Think about it: What do you think would happen if…
▪ The Mitochondria or Chloroplasts stopped working?
▪ The Plasma Membrane didn’t do its job?
▪ The Nucleus stopped directing activities?
1. How are prokaryotic and eukaryotic cells similar?a) Both contain a nucleus
b) Both contain ribosomes
c) Both contain membrane-bound organelles
d) Both contain cell walls2. This diagram shows a plant cell. Which structure is
found in a plant cell but absent in an animal cell?a) 1
b) 2
c) 3
d) 4
Found only in plant cells, this organelle converts radiant energy to chemical energy through the process of photosynthesis.
This organelle is significantly larger in plant cells in order to aid in keeping plants upright. If this organelle is not full, the plant will wilt.
The folded inner membranes of this organelle provide more surface area for increased ATP production.
These small organelles are vital for the production of proteins in a cell.
This organelle controls cell functions and houses DNA.
This organelles unique structure allows for the selective passage of molecules into and out of the cell.
Nucleus▪ “Brain of the cell”-controls cell functions and
stores DNA Mitochondria
▪ “Powerhouse of the cell”-makes energy through cellular respiration; folded inner membrane provides lots of surface area for cell processes
Cell membrane▪ “Gate of the cell”-Double membrane structure
composed of lipids-controls what goes in and out
Ribosomes
▪ Site of protein synthesis (makes proteins); attached or free floating
Cytoplasm
▪ Jelly/gel that surrounds cells-keeps organelles where they should be
Vacuole
▪ “Storage center”-holds water, food, etc.-large in plants due to Turgor Pressure
Chloroplast
▪ Plants only-uses sunlight to convert to sugar through process of photosynthesis
Cell wall
▪ Plants only-carbohydrate called cellulose provides rigid structure that protects and supports cell
Lysosome
▪ “Garbage can”-animals only. Uses enzymes to digest waste products
Endoplasmic Reticulum-Network of membranes that fold, modify, and transports proteins throughout the cell
Golgi Apparatus-receives proteins and lipids (fats); modifies, sorts, and packs them; works closely with the ER
Cells all begin as undifferentiated
Undifferentiated=not different; the same
DNA determines the type of cell (ex. nerve cell, muscle, blood…)
We will talk more about this later!
Mitochondria? Why? Chloroplasts? Why?
Cell organelles can be more concentrated based on needs!
http://www.glencoe.com/sites/common_assets/science/virtual_labs/E08/E08.html
▪ Interactive cell where you match organelle to name and function
https://quizlet.com/3082892/cell-organelles-review-flash-cards/
▪ Quizlet with flashcards, games, and quizzes
Decide whether the cell is plant or animal. Next, label the parts with the appropriate name.
Structure and Adaptations
A “multicellular” organism is composed of many cells (ex. You are composed of many animal cells; plants are composed of many plant cells)
“Unicellular” means they are composed of a single cell!
▪ Ex. Bacteria, protozoa, euglena
Unicellular organisms have many structures that help them survive
▪ Contractile vacuoles
▪ Cilia
▪ Flagella
▪ Pseudopods
▪ Eyespots
Stores excess water that enters the cell, and expels it to the exterior
▪ It expands when filling with water, then contracts, expelling the contents back out
▪ Found in: protists + unicellular algae
https://www.youtube.com/watch?v=pahUt0RCKYc
A dark area that functions in light reception; influences motion so that the organism can move toward/ away from light▪ Toward (positive phototaxis)
▪ Away (negative phototaxis)
▪ Found in: green algae; photosynthetic unicellular organisms
Cilia▪ Many hair like structures▪ Often used for movement▪ Non-motile cilia serve as
sensory organelles
Flagella▪ Single, whip like tail used
for movement▪ Found in: bacteria,
protists, specialized plant, animal and fungi cells
https://www.youtube.com/watch?v=QGAm6hMysTA
Pseudopods
▪ “False feet” that help the unicellular organism move about
▪ Sometimes used to obtain food (phagocytosis)
https://www.youtube.com/watch?v=PsYpngBG394
Recall that “taxis” is an innate behavior in response to an outside stimuli
Movement in response to chemicals (“chemo”). Some single celled organisms direct their
movement according to chemicals in their environment
Found in bacteria and single-cell or multicellular organisms
▪ Find food (e.g., glucose)
▪ Flee from poisons (e.g., phenol)
▪ Critical to early development
Movement toward or away from light. Many plant-like unicellular organisms will
move toward light to better photosynthesize, just like plants will tilt toward the window
▪ Positive phototaxis: if the movement is in the direction of increasing light intensity
▪ Negative phototaxis: if the movement is in the opposite direction of light intensity
https://www.youtube.com/watch?v=2koAGkgmiqg
Challenge: Identify the following cells:
Take a few minutes to study!