Transcript Describing Matter & Energy

What is life?
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The characteristics of living things
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What is an organism? Give a few examples.
6 important characteristics:
1.
Made of cells
4.
2.
Contain similar chemicals 5.
Respond to their surroundings
3.
Use energy
Can reproduce
6.
Grow and develop
1. All organisms are made of cells
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A cell is the basic unit of structure (the way it’s made)
and function (the job it performs).
Cells are similar in being the basic building blocks of
animal and plant tissues. They are composed of complex
chemicals and can perform tasks necessary to life.
Who can give an example of a multicellular organism?
What about a unicellular organism?
What is life?
2. Cells contain similar chemicals
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The most abundant chemical in a cell is water
Carbohydrates are the main energy source
Proteins and lipids are the building materials
Nucleic acids are the genetic material (the instructions
that direct cell’s activities)
3. Cells use energy to do what living things must do
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As you sit there, your eyes and brain are busy learning,
your stomach and intestines are digesting food, your cells
may be repairing themselves, etc.
4. Living things grow and develop
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Who can describe growth and development?
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Growth is the process of becoming larger. Development is the
process of change that occurs during an organism’s life to
produce a more complex organism.
To grow and develop, energy is used to create new cells
What is life?
5. All organisms react to changes in their environment
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A stimulus is a change in an organism’s surroundings that
causes it to react. The response is the reaction.
Who can explain and give examples of external versus
internal stimuli?
6. All organisms have the ability to reproduce, or
produce offspring that are similar to the parents
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How do growth and development differ?
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Life comes from life – proved by Redi & Pasteur
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The mistaken idea that living things arise from non-living
things is called spontaneous generation
What is life?
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Living things must satisfy their basic needs for
energy, water, living space and stable internal
conditions
Some organisms use food as their energy source;
they use the sun’s energy along with carbon dioxide
& water to make their food
How do heterotrophs depend on autotrophs for
energy?
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Heterotrophs can not produce their own food, so they
obtain their energy from the food they eat. They either
eat autotrophs and obtain the energy stored in the food
made by the autotrophs, or they eat other heterotrophs
that eat the autotrophs.
What is life?
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Water is required to obtain chemicals from
surroundings, break down food, grow, move
substances within their bodies and reproduce
Organisms need a place to live and may compete
for it
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What advantage do animals have over plants in terms of
living space?
Homeostasis allows for the maintenance of stable
internal conditions
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Who can provide some examples of homeostasis?
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The human body’s regulation of temperature
Barnacles can close up it’s hard outer plates, trapping droplets of
water inside to keep its body moist until the next high tide
Discovering Cells
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Around 1590, the invention of the microscope made
it possible for people to discover and learn about
cells
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A simple microscope has one lens (like a hand lens), a
compound microscope has multiple lenses
Robert Hooke, Anton van Leeuwenhoek, Matthias
Schleiden & Theodor Schwann and other important
scientists - their findings led to the cell theory
Discovering Cells
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The cell theory states:
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All living things are composed of cells
Cells are the basic unit of structure and function in living
things
All cells are produced from other cells
This theory holds true for all living things,
regardless of size or complexity, since all living
things are made of cells
Discovering Cells
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Light Microscope
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2 important properties of microscopes are magnification
and resolution
The lens or lenses in a light microscope magnify an
object by bending the light that passes through them
The microscopes used by the early scientists were all light
microscopes
Electron Microscope
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Use a beam of electrons instead of light to examine a
specimen
Has much better resolution than a light microscope
Discovering Cells
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How did the invention of the microscope affect scientists’
understanding of living things?
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Explain the 3 main ideas of the cell theory.
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According to the cell theory, all living things are made of cells, cells
are the basic building blocks of life, and they are the only source of
new cells.
How does a compound microscope use lenses to magnify an
object?
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It made it possible for people to discover and learn about cells
Light passing through the first lens magnifies the object; then light
passing through the second lens magnifies the image of the object
even more.
Explain why both magnification and resolution are important
when viewing a small object with a microscope.
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Magnification makes an object larger while resolution sharpens the
image
Looking Inside Cells
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Cells contain tiny cell structures called organelles,
which carry out specific functions in the cell
Cells of plants and other organisms have cell walls;
the cells of animals and other organisms lack cell
walls
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What is the function of the cell wall?
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All cells have cell membranes – the structure you
pass right after passing through the cell wall
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Explain the function of the cell wall.
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To help protect and support the cell
Controls what substances come into and out of a cell
The nucleus is the cell’s brain or control center,
directing all of the cell’s activities
Looking Inside Cells
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Inside the Nucleus:
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Nuclear membrane – similar to the cell membrane
Chromosomes – formed when chromatin strands coil and
condense. Chromatin contains the genetic material.
Nucleolus – where ribosomes are made. Ribosomes are
the organelles where proteins are produced.
Outside of the Nucleus:
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*Check your ch 4 key terms for definitions*
Mitochondria
Endoplasmic Reticulum
Ribosomes
Golgi Bodies
Chloroplasts
Vacuoles
Lysosomes
Looking Inside Cells
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Bacterial cells
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Smaller than plant and animal cells
Does not contain a nucleus – prokaryotes. (those that do
contain a nucleus plus the other organelles are eukaryotes)
Genetic material is found in the cytoplasm
Contain ribosomes, but none of the other organelles found
in plant and animal cells
Structure & Function of cells – similar to the structure
& function of organisms
The bodies of many multicellular organisms have four
levels of organization
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Cells  tissues  organs  organ systems
Describe each of the levels that complex organisms exhibit
Looking Inside Cells
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Choose one of 2 activities:
Create a model of the animal or plant cell (or both)
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You can draw and color it, or use colored paper to create
the pieces and fit it all together
Create a key that identifies what each of the organelles
are and what their function is
Use pages 142 – 143 as guidelines
A cell is similar to the human body – match the
cell’s organelles to human body parts that carry out
similar functions.
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For example, the cell’s nucleus would be like the human
brain.
Also, develop a way that will help students link the
organelle to it’s specific function.
Introduction to Genetics
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Traits are the physical characteristics that an
organism can pass on to its offspring
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Remember that chromatin contains genetic material
that directs the cell’s activities
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Describe traits of humans? What about traits of plants?
This genetic material also plays a role in heredity
Organisms resemble their parents because they
inherit genetic material from their parents.
DNA, or deoxyribonucleic acid, carries info from the
parent to the offspring
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A gene is a section of DNA that controls an inherited trait
Introduction to Genetics
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Bacteria produce asexually by dividing into 2 cells
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The genes are identical to the parent organism
Other organisms such as plants and animals produce
sexually
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New organisms result from the combination of genetic
material from 2 parent organisms
The traits are determined by genetic material from both the
male and female parents
Genetic material is re-sorted, over and over, each time
reproduction occurs  this is why you resemble your
parents more than your grandparents or greatgrandparents
Why aren’t the offspring of sexually reproducing organisms
identical to either of their parents?
Introduction to Genetics
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In selective breeding, organsims that have certain
desired traits are mated to produce offspring with the
desired traits of both parents. The desired traits are
produced by the combination of genetic material that
the offspring inherit from both of their parents.
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Explain why selective breeding would be important to
someone.
Traits of organisms can change over generations
naturally  this is necessary to help organisms
survive better in their environment