Transcript unit 5 notes - Flushing Community Schools

Unit 5 Notes
I CAN A
 The Characteristics of Living Things
 Organisms = living things
 All living things:
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Have cellular organization
Contain similar chemicals
Use energy
Respond to their surroundings
Grow and develop
Reproduce
 Cellular Organization
 Cell = the basic unit of structure and function in an
organism



A microscope is needed to see most cells
Unicellular Organism = single-celled organism
 Ex: a bacterium or bacteria
Multicellular Organism = many-celled organism
 In Multicellular organisms:
 Each cell is specialized to do a certain task
 Ex: muscle and nerve cells are found in humans
 The Chemicals of Life
 All cells are made of chemicals
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Carbohydrates provide cells with energy
Proteins and lipids are the building materials of cells
Nucleic acids carry genetic material which controls the cell’s
activities
The most abundant chemical found in living cells is water
 Energy Use
 An organism’s cells use energy to perform all functions
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
Ex: stomach cells use energy to digest food
Ex: blood cells use energy to move chemicals around your
body
 Response to Surroundings
 Stimulus = a change in an organism’s surroundings
that causes the organism to react

Stimuli (plural) include:
 Temperature
 Light
 Sound
 Response = an action or change in behavior
 -Do some examples in class
 When a plant grows toward light.
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The light would be the stimulus
The planting growing toward the light is the response
 Growth and Development
 Growth = the process of becoming larger
 Development = the process of change that occurs
during an organism’s life to produce a more complex
organism

Ex: you have gotten taller with age (growth), but you have
also gotten smarter (development)
 Reproduction
 Reproduce = the ability to produce offspring that are
similar to the parents
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Ex: birds lay eggs that develop into birds who look like their
parents
Ex: apples produce seeds that develop into apple trees
 Four hundred years ago people believed that life could
appear from a nonliving material call spontaneous
generation however we now know that living things
are only produced by other living things.
 This was proven by two scientist Francesco Redi and
Louis Pasteur
What Is
Life?
Four -hundred
years
ago people believed that life
could appear from a nonliving material call
spontaneous generation however we now know
that living things are only produced by other
living things.
- What Is Life?
I CAN B
 What is a Virus?
 Virus= a tiny, nonliving particle that enters and then
reproduces inside a living cell.

No organisms are safe from viruses!
 (remember an organism is a living thing)
 Characteristics of Viruses
 Viruses are considered non living because they do not
have all the characteristics essential for life
 The only way in which viruses are like organisms is they
are able to multilpy.
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Although viruses can multiply, they do so differently
than organisms. Viruses can multiply only when they
are inside a living cell.
 Virus Sizes
 Viruses are much smaller that cells (even the smallest
cells in bacteria)
 Measured in units called “nanometers” one billionth of
a meter.
- Viruses
Show size of viruses on “Cells Alive Web Page”
- Viruses
 How Viruses Multiply
 Once inside a cell, a virus’s genetic material takes over
many of the cell’s functions
 It instructs the cell to produce the virus’s proteins and
genetic material.
 These proteins and genetic material then assemble into
new viruses
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Some viruses take over immediately (Active Viruses) cold
Some viruses wait for a while (Hidden Viruses) cold sore
- Viruses
- Viruses
 Viruses and the Living World
 Viruses and Disease
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Some viral disease keep people sick for only a short period of
time; (such as a cold)
Others can be fatal (such as AIDS)
Viruses can also cause diseases in organisms other than
humans such as:
 Apple trees infected by apple mosaic virus
 Dogs and cats can get rabies
I CAN C
 The Bacterial Cell
 There are more bacteria in your mouth than there are
people on Earth!!
 Although there are billion of bacteria on Earth, they
were not discovered until the late 1600’s.
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Anton Van Leeuwenhoek discovered them by accident when
looking at scrapings from his teeth under a microscope.
 Bacteria= single celled organism
 Bacteria are prokaryotes. The genetic material in their cells
is not contained in a nucleus.
- Bacteria
Bacteria are
prokaryotes. The
genetic material in
their cells is not
contained in a
nucleus
 Cell Shapes
 Three basic shapes:
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Spherical
Rod-like
Spiral
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The shape of the cell helps scientists identify the type of
bacteria.
 For example, bacteria that cause strep throat are spherical.
Live in guts of Surgeon
Fish
Found in intestines of
humans and is used to
manufacture yogurt.
Can cause
meningitis
 Cell Sizes
 The largest known bacterium is about as big as a period
in your book.
 Most bacteria are much smaller.

The bacterium that causes strep throat are about .5 to 1
micrometer in diameter. A micrometer is one millionth of a
meter.
 Reproduction
 When bacteria have plenty of food, the right
temperature, and other suitable conditions, they thrive
and reproduce frequently.
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It is a good thing that growing conditions for bacteria are
rarely ideal. Otherwise, there would be no room on Earth for
other organisms!
 Asexual Reproduction
 Asexual Reproduction= a reproductive process that
involves only one parent and produces offspring that are
identical to the parent.

During binary fission the cell first duplicates its genetic
material and then divides into two new cells, each cell gets a
complete copy of the genetic material as well as some of the
parent’s ribosomes and cytoplasm.
Reproduces by binary fission every 20
minutes.
 Sexual Reproduction
 Sexual Reproduction= involves two parents who
combine their genetic material to produce a new
organism, which differs from both parents.
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This results in new bacteria that are genetically different from
the parent cells
 The Role of Bacteria in Nature
 Oxygen Production
 Food Production
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Pasteurization= food is heated to a temperature that is high
enough to kill most harmful bacteria without changing the
taste.
 Environmental Recycling
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Decomposers= organisms that break down large chemicals
in dead organisms into small chemicals
 Environmental Cleanup
 Health and Medicine
 Treating Infectious Diseases
 Bacterial Diseases
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Can be cured with medications known as antibiotics
 Antibiotic= a chemical that can kill bacteria without harming
a person’s cells
 Example: Penicillin (works by weakening the cell walls of
some bacteria and causing the cells to burst.
 Antibiotic resistance= results when some bacteria are
able to survive in the presence of an antibiotic.
- Viruses, Bacteria, and Your Health
 Treating Infectious Diseases Cont.
 Viral Diseases
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Unlike bacterial diseases, there are currently no medication
that can cure viral infections.
 Medications help relieve symptoms
- Viruses, Bacteria, and Your Health
 Preventing Infectious Diseases
 Vaccine= a substance introduced into the body to
stimulate the production of chemicals that destroy
specific viruses or bacteria.

May be made from dead or altered viruses or bacteria that
puts our body on “alert” for that disease.
 Vaccines are important tools that help prevent the spread of
infectious diseases.
I CAN D,E and F
 In 1663, Robert Hooke observed the first cells while
looking at cork under his microscope
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He called them “cells” because they reminded him of the
small rectangular rooms called cells
 At about the same time, Anton van Leeuwenhoek
observed pond water and teeth scrapings
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He saw “animalcules” (little animals) in the water and bacteria
from the teeth
 Development of the Cell Theory
 In 1838, Matthais Schleiden concluded that all plants
are made of cells
 In 1839, Theodor Schwann concluded that all animals
are also made of cells
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Therefore, all living things are made of cells
 In 1855, Rudolf Virchow proposed that new cells are
formed only from existing cells
 The observations and conclusions of these five men led
to the cell theory:
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All living things are composed of cells
Cells are the basic units of structure and function in living
things
All cells are produced from other cells
Examples of Cells
Amoeba Proteus
Plant Stem
Bacteria
Red Blood Cell
Nerve Cell
 Inside tiny cells are even smaller structures called
organelles
 Organelles = tiny cell structures which carry out
specific functions within the cell
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Organelles are to cells, as organs are to the human body!
 See pgs. 20 & 21 (know all structures/functions)
 Cell wall = in plant cells, a stiff wall that surrounds the
cell membrane giving the cell a box-like shape
 Cell membrane = protects the cell and regulates what
enters and leaves the cell
“Typical” Plant Cell
- Looking Inside Cells
 Nucleus = directs all of the cell’s activities, including
reproduction
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Nuclear membrane = protects the nucleus and regulates
what enters and leaves the nucleus
Chromatin = strands of genetic material which direct the
functions of the cell
Nucleolus = where ribosomes are made
 Organelles in the Cytoplasm
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Cytoplasm = area between the cell membrane and the
nucleus filled with a gel-like fluid
- Looking Inside Cells
Mitochondria = rod-shaped organelles which produce most of the
cell’s energy
- Looking Inside Cells
Endoplasmic reticulum (ER) = network of passageways that
carries materials from one part of the cell to another
Ribosomes = produce proteins (can be free-floating or attached to
the ER)
- Looking Inside Cells
Golgi bodies = receives materials from the ER and sends them to other
parts of the cell
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Chloroplasts = in plant cells, the site of photosynthesis
Vacuoles = stores food, water, waste and other materials
Lysosomes = contain chemicals which break down food
particles and worn-out cell parts
- Looking Inside Cells
 Cellular Organization
 In many celled organisms, cells are often organized into
cells, tissues, organs, and organ systems.
 Cells make tissues
 Tissues make organs
 Organs work together in an organ system
 Specialized Cells
 In many celled organisms, cells are often organized into
tissues, organs, and organ systems.
 Cells – Tissues – Organs – Organ System
 Some cells serve specific functions, therefore have
specific structures
 Examples: Figure 14 pg. 23
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Nerve cells with “arms” through which to pass messages
Red blood cells which are flexible to fit through blood vessels
 Elements and Compounds
 Element = any substance that cannot be broken down into
simpler substances
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Examples: hydrogen (H), oxygen (O)
 Atom = the smallest unit of an element
 Examples: one atom of hydrogen, one atom of oxygen
 Compound = formed when two or more elements combine
chemically

Example: water (H2O) is made of hydrogen and oxygen
 Molecule = the smallest unit of a compound
 Example: one water molecule is made of two hydrogen atoms and
one oxygen atom (see pg. 33)
- Chemical Compounds in Cells
Compounds
 Inorganic and Organic Compounds
 Organic compounds = compounds which contain
carbon
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Four groups of organic compounds:
 Carbohydrates
 Lipids
 Proteins
 Nucleic acids
 Inorganic compounds = compounds which do not
contain carbon
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Exception: Carbon dioxide (CO2) is considered inorganic
 Carbohydrates
 Carbohydrate = an energy-rich organic compound
made of the elements carbon, hydrogen, and oxygen
 Examples: sugars, starches
 Proteins
 Protein = large organic molecule made of carbon,
hydrogen, oxygen, nitrogen, and sometimes sulfur
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Amino acids = small molecules which make proteins (20
different kinds)
Enzyme = type of protein that speeds up a chemical reaction
in a living thing
 Lipids
 Lipid = an energy-rich organic compound made of
carbon, hydrogen, and oxygen
 Examples: fats, oils, waxes, cholesterol
 Lipids contain even more energy than carbohydrates!
 Nucleic Acids
 Nucleic acid = very large organic molecule made of
carbon, oxygen, hydrogen, nitrogen, and phosphorus
 Two kinds:
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DNA (deoxyribonucleic acid) – genetic material
RNA (ribonucleic acid) – produces proteins
- Chemical Compounds in Cells
Analyze together
using questions on
page 29.
- Chemical Compounds in Cells
Water and Living Things
* Water makes up about 2/3 of the human
body
* Without water, most chemical reactions
within cells could not take place
* Water also helps give cells their size and
shape
* Water helps keep the temperature of cells
from changing rapidly
I CAN G
 The Cell Membrane as a Gatekeeper
 Selectively permeable = describes the cell membrane’s
ability to allow some substances through and not others
 Three methods by which substances move into or out of
a cell:
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Diffusion
Osmosis
Active transport
- The Cell in Its Environment
 Diffusion – Molecules in Motion
 Diffusion = the process by which molecules tend to
move from an area of higher concentration to an area of
lower concentration
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Molecules are always moving, so as they bump into each other
they spread out
 Osmosis – The Diffusion of Water Molecules
 Osmosis = the diffusion of water molecules through a
selectively permeable membrane
- The Cell in Its Environment
- The Cell in Its Environment
 Active Transport
 Passive transport = the movement of materials through a
cell membrane without using energy
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Passive transport moves substances from high concentration to low
concentration
 Active transport = the movement of materials though a cell
membrane using energy

Active transport moves substances from low concentration to high
concentration
 Transport proteins can also “pick up” molecules and move
them into or out of a cell
 Sometimes, cells can also engulf particles, taking them into
the cell (Figure 19, p. 37)
- The Cell in Its Environment
I CAN H
 Photosynthesis
 Photosynthesis = the process by which a cell captures
the energy in sunlight and uses it to make food
 Sources of Energy
 Nearly all living things obtain their energy either directly
or indirectly from the energy of sunlight captured during
photosynthesis
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Autotroph = an organism that gets its energy directly from
the sun
 Example: plants make their own food
Heterotroph = an organism that gets its energy indirectly
from the sun
 Example: animals cannot make their own food
- Photosynthesis
 The Two Stages of Photosynthesis
 Stage 1: Capturing the energy in sunlight
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The chlorophyll (green pigment) in the chloroplasts serve as
solar cells to collect the sun’s energy
 Stage 2: Turning the captured energy into sugars
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Requires two raw materials, H2O and CO2
CO2 enters through stomata (leaf pores)
 The Photosynthesis Equation
 6 CO2 + 6 H2O (light energy) C6H12O6
 C6H12O6 = glucose (a sugar)
+ 6 O2
- Photosynthesis
I CAN I
 Cellular Respiration
 Storing and Releasing Energy
 During photosynthesis, plants capture the energy from
sunlight and store it as carbohydrates (like glucose)
 When the plant cells need energy, they “withdraw” the
stored carbohydrates
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Similarly, your body burns carbohydrates when its cells need
more energy (like when you’re running)
 Respiration
 Respiration = the process by which cells “withdraw”
energy from glucose
 During respiration, cells break down simple food
molecules and release the energy they contain
 The Respiration Equation
 C6H12O6 + 6 O2  6 CO2 + 6 H2O + energy
 The Two stages of Respiration
 Stage 1: Glucose is broken down in the cytoplasm
 Stage 2: Molecules are broken down further in the
mitochondria – energy is produced
- Respiration
 Comparing Photosynthesis and Respiration
 Photosynthesis and respiration are opposites!
 The products of one are the raw materials of the other,
creating a circular cycle
- Respiration
 Fermentation
 Some organisms live where there is no oxygen, so they
cannot undergo photosynthesis or respiration
 Instead they use fermentation
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Fermentation = an energy-releasing process that does not
require oxygen
Fermentation provides energy for cells without using oxygen
 Two types of fermentation:
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Alcoholic fermentation: produces alcohol, carbon dioxide,
and small amounts of energy
 Used to make carbonated soda and root beer
Lactic-acid fermentation: occurs in your body when oxygen
is used up more quickly than it can be replaced
 This is what gives you sore muscles after working out
Do you know what organelles are? Well,
we have organs… cells have organelles.
We have a heart, lungs, and kidneys;
they have a nucleus, mitochondria.. blah
blah blah!
Got it?
Good!
Do you know all of the names and
functions of all of the organelles?
You should know most but
the good news is … you don’t have to
know them all for this! Woo Hoo
You DO have to know a few
important ones. Let’s see…
FIRST…LET’S LOOK AT THE CELL….
Now, let’s remove the confusing stuff.
Yesssssss….. Much Better =)
photosynthesis and respiration are…
1) Nucleus 2) Cell membrane
3) Mitochondria 4) Chloroplast
5) Cell wall
Sound familiar?
On the next slide, find them on
the picture!!
3) Mitochondria 4) Chloroplast
5) Cell wall
Where are the chloroplasts and cell
wall????
YUP… you’re right. You only find those in
plant cells. THIS is an animal cell.
THIS is a plant cell
This is a chloroplast
The cell wall is the THICK layer outside
the cell membrane.
So there ARE some differences
between plant and animal cells.
What type of cells have cell walls?
Plant Cells
What type of cells are sometimes drawn to
look rectangular?
Plant Cells
More differences….
What type of cells have a nucleus?
THEY BOTH DO!! This is where both plants
and animals carry their DNA!!!!
What type of cells have chloroplasts?
Plant Cells
This is why PLANTS (NOT ANIMALS) can make their own
food!!!!!!
Let’s focus in on the …
You
See??
They’re green!
This is why plants are green!
Chloroplasts
This is where plants MAKE their own food. They can
make enchiladas, tacos, and sometimes quesadillas
whenever they want.
Ha whatever. All that they can make is
glucose sugar through a process
called…?
Photosynthesis!!!!!!!
Carbon
Dioxide
Oxygen
Water
Sugar
Energy
Okay… so what goes in and out of
plants in photosynthesis??
CO2 + H20 + ENERGY  C6H12O6 + O2
Carbon Dioxide, Water and suns energy yields sugar and oxygen
So what about…
NOT
GREEN
Mmmm… if photosynthesis
occurs in chloroplasts, what
process occurs in
mitochondria?
Cellular Respiration
We use the food that we eat (sugar) to give us
energy! Without this energy, we would die =) (If
you don’t eat, you starve to death).
Carbon
Dioxide
Oxygen
Water
Sugar
Energy
Ummm….
Carbon
Dioxide
Oxygen
Water
Sugar
Energy
Cellular Respiration
Carbon
Dioxide
Oxygen
Water
Sugar
Energy
Ahhhhh….
Carbon
Dioxide
Oxygen
Water
Sugar
Energy
Cellular Respiration
Brain cells kicking in yet??
Carbon
Dioxide
Oxygen
Water
Sugar
Energy
Yeah buddy…
Carbon
Dioxide
Oxygen
Water
Sugar
Energy
Cellular Respiration
Yeah! It’s the exact opposite of
photosynthesis!
Carbon
Dioxide
Oxygen
Water
Sugar
So you think you can
remember what goes
in and out? Study for
a second… =)
Energy
So what goes in and out of
mitochondria during cellular
respiration?
C6H12O6 + O2 CO2 + H20 + ENERGY
and Oxygen Yields Carbon Dioxide, Water and Energy
Sugar
Okay ready??
Since photosynthesis in the chloroplasts
looks like this…
CO2 + H20 + ENERGY  C6H12O6 + O2
Cellular respiration in the mitochondria looks
like …
GUESS!!
C6H12O6 + O2 CO2 + H20 + ENERGY
TOO EASY!!!!!!!
I CAN J
 The Cell Cycle
 Cell cycle = the regular sequence of growth and division
that cells undergo

See p. 58-59
 Stage 1: Interphase
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Interphase is the first stage (of 3) of the cell cycle
Interphase is the period before cell division occurs
 The cell grows into its mature size
 The cell makes a copy of its DNA (process called replication)
 The cell prepares to divide into two cells
 Stage 2: Mitosis
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Mitosis is the second stage (of 3) of the cell cycle
Mitosis is the stage during which the cell’s nucleus divides
into two new nuclei
Four Phases of Mitosis:
 Phase 1 of Mitosis: Prophase
 Chromatin in nucleus condenses to make chromosomes
 Spindle fibers form a bridge between the ends of the cell
 Nuclear membrane breaks down
- Cell Division

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Phase 2 of Mitosis: Metaphase
 Chromosomes line up across the center of the cell
 Each chromosome attaches to a spindle fiber at its
centromere (holding the chromatids together)
Phase 3 of Mitosis: Anaphase
 Centromeres split
 The two chromatids separate
 One chromatid moves along the spindle fiber to one end of
the cell
 The other chromatid moves to the other end
 The cell becomes stretched out as the opposite ends pull
apart

Phase 4 of Mitosis: Telophase
 The chromosomes begin to stretch out and lose their rodlike
appearance at the ends of the cell
 A new nuclear membrane forms around each region of
chromosomes
 Stage 3: Cytokinesis
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
Cytokinesis is the third stage (of 3) of the cell cycle
The cytoplasm divides, distributing the organelles into each of
the new cells
Each new (daughter) cell has the same number of
chromosomes as the parent cell
- Cell Division
 Length of the Cell Cycle
 See Figure 11, p. 60
 Example: a human liver cell completes one cell cycle in
about 22 hours

Notice how long interphase is (21 hours) compared to mitosis
and cytokinesis together (1 hour)!
 DNA Replication
 A cell makes a copy of its DNA before mitosis occurs

This ensures that each daughter cell has all the genetic
information it needs to carry out its activities
- Cell Division
 The Structure of DNA (Figure 14, p. 61)

DNA resembles a twisted ladder called a double helix
 The two “sides” are made of a sugar called deoxyribose and
phosphates
 The “rungs” are made of pairs of nitrogen bases
 Nitrogen bases: adenine (A), thymine (T), guanine (G)
and cytosine (C)
 Note that A only pairs with T, and G only pairs with C
 During replication, the DNA is “unzipped” and new
nitrogen bases attach

See Figure 15, p. 62
- Cell Division
- Cell Division
Cancer
 What Is Cancer?
 Cancer = a disease in which cells grow and divide
uncontrollably, damaging the parts of the body around
them
 How Cancer Begins


Scientists believe that cancer begins when something
damages a portion of the DNA in a chromosome, changing
the DNA
 Mutation = a change in the DNA following damage
Mutations disrupt the normal cell cycle, causing cells to divide
in an uncontrolled way
 How Cancer Spreads



First, one cell develops abnormally
As that cell divides, more and more abnormal cells like it grow
nearby
In time, these cells form a tumor
 Tumor = a mass of abnormal cells that develops when
cancerous cells divide and grow uncontrollably
- Cancer
 Treating Cancer
 Doctors usually treat cancer in one of three ways:



Surgery
 Doctors can sometimes completely remove the cancerous tumor
through surgery, and the person may be cured
Radiation
 If the tumor cannot be completely removed, or the cancer has
spread, doctors may use radiation
 Radiation (beams of high-energy waves) target fast-growing cells
and destroy them
Drugs that destroy cancer cells
 If neither surgery nor radiation are options, doctors may prescribe
chemotherapy
 Chemotherapy = the use of drugs to kill cancer cells
 Chemotherapy has many, many bad side-effects
 Cancer Prevention
 Almost 2/3 of all cancer deaths are caused by tobacco or
unhealthy diets
 Cancer-causing actions

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Using tobacco (smoking cigarettes) can cause lung cancer
Drinking alcohol can cause liver or kidney cancer
Eating fatty foods can cause stomach or intestinal cancer
Tanning or not using sunscreen can cause skin cancer
(melanoma)