Transcript Chapter 1: Cells, Reproduction, and Heredity

Chapter 1: Cells,
Reproduction, and Heredity
Cells are the basic units of all living things. Groups
of cells form tissues that gather into organs and
into organ systems. All of the characteristics of an
organism are dictated to DNA
Lesson 1: How Do Plant and Animal Cells Differ?
Lesson 2: How Do Cells Work Together?
Lesson 3: How Do Cells Reproduce?
Lesson 4: How Are Traits Inherited?
Chapter 1: Cells, Reproduction,
and Heredity
• Objectives
– Explain the cell theory
– Describe the functions of the various parts of plant and
animal cells
– Describe how cells are organized in multicellular organisms
– Describe the functions of organs and organ systems
– Describe the role of DNA in cell reproduction
– Compare and contrast the processes of mitosis and meiosis
– Recognize that an animal’s or a plant’s traits are inherited
from its parents
– Describe how dominant and recessive genes affect
inheritance of traits
How Do Plant and Animal Cells Differ?
32 – The Cell Theory
30 - Lesson 1 -
It was almost 200 years after the first
microscope, that scientists began
studying cells in detail.
Scientists noticed that every living
organism they studied had cells.
They then developed a three-part
theory about cells.
How Do Plant and Animal Cells Differ?
32 – The Cell Theory
30 - Lesson 1 -
Three-Part Theory
1. Cells are the building blocks of life
a. All living things are made up of cells.
2. All life processes take place in
cells
a. Growth and reproduction
3. All new cells are produced from
existing cells
a. Living things begin life as a single
cell, then divides. Each single cell
divides until they begin to take on
different function.
What are the three parts of the cell
theory?
• Cells are building blocks of life
• All life processes take place in cells
• All new cells are produced from existing cells
34-The Part of a Cell
Both Animal and Plant cells have organelles (which keep the cell alive
and healthy) and cytoplasm (which holds them in place).
Plant Cell
Contain organelles
called chloroplast
Has a cell wall
One large vacuole
takes up most of
the cell
animal Cell
Cell Membrane
Organelles
called vacuoles
Nucleus
Have
mitochondria
Cytoplasm
Nucleus
Membrane
Don’t have
Cell Walls
Vacuoles are small
and have more
than 1
Vocabulary
34 – Chloroplasts – make the plant’s food
by the process of photosynthesis
34 – Cell Wall – A stiff outer layer that
surrounds and protects the cell and give
it shape.
35 – Nucleus – The cell’s control center,
directs all of the activities that take place
inside the cell.
35 – Chromosomes- The structures that
carry an organism’s genetic information.
What are the functions of different
organelles in plant and animal
cells?
•
•
•
•
The nucleus holds chromosomes
Mitochondria release energy from food
Vacuoles store food and wastes
Chloroplasts manufacture food
36 – The Nucleus
The chromosomes in the nucleus
contain instructions for all cell
activities.
Chromosomes are made up of DNA
and proteins.
DNA contains the codes that
determine physical characteristics
such as flower color in plants and
hair color in humans.
Vocabulary
36 – DNA – A chemical that provides
detailed instructions to the cells about
every function of life.
Why is the nucleus considered
the control center of a cell?
• The chromosomes in the nucleus have
instructions for all cell activities.
Lesson 1 Review
• Complete numbers 1-2 and 4-6 as a group.
• I will come around and stamp answer that are
correct, all must have the same answer as that
on the paper I stamp.
40 - Lesson 2 – How do cells work together?
40 – Specialized cells and tissues
Specialized cells with similar structure and
function form a tissue. This is the next level of
organization above cells in both plants ad
animals. There are 4 tissue types in humans.
1. Epithelial tissue-contains cells that are packed
together tightly
2. Connective tissue-add support and structure to
the body, fills spaces and stores fat.
3. Muscle tissue-like elastic, job is to contract and
relax.
4. Nerve tissue-found in brain, spinal cord, nerves
and sensory receptors. These are messages that
are sent to the brain.
Vocabulary
40 – Tissue – Specialized cells with similar
structure and function
List the steps of how tissues help
your hand move when you touch a
hot stove
• Nerves in your hand send a message to the spinal cord.
• A reflex takes place when nerves in the spinal cord send
signals to muscles in your hand that cause you to jerk it
off the stove.
• Nerves send a message up the spinal cord.
• The brain receives pain from the burn.
40 - Lesson 2 – How do cells work together?
42 – Organs
An organ is a structure made up of at least two
types of tissues that work together to perform
a specific job in the body.
The different organs are:
Brain
Heart
Blood Vessels
Lungs
Sense Organs
Stomach
Small Intestine
Liver
Pancreas
Vocabulary
42 – Organ– A structure made up of at
least two types of tissues that work
together to perform a specific job I the
body.
Describe the levels of organization
from cells to organs
• Cells make up tissues
• Tissues make up organs
40 - Lesson 2 – How do cells work together?
42 – Organs Systems
An organ system is a group of organs that work
together to perform a specific function.
Organ Systems are:
Digestive: digests food
Respiratory: controls breathing
Circulatory: Gives body oxygen
Skeletal & Muscular: Provide & support movement for
body
Integumentary: Skin, hair & nails that cover body
Excretory: Removes wastes from blood
Reproductive: Produces individuals
Endocrine: Makes and sends chemicals called hormones to
help control body activities
40 - Lesson 2 – How do cells work together?
42 – Organs Systems
Plants have organs and organ systems.
Roots, stems and leaves ore some of them.
Inside the stem:
Xylem tissue & Phloem: transport water and
nutrients
Epithelial Tissue
Root System: anchors the plant in the ground.
Shoot System: Stems and Leaves
Stems: support the plant
Leaves: make food
Describe the path of a blood cell
as it leaves the heart until it returns
to the heart.
• A red blood cell leaves the heart in an artery and goes to the
lungs.
• In the lungs, the red blood cell picks up oxygen.
• The blood cell ten leaves the lungs and goes back to the heart.
• Next, the blood cell leaves the heart through the aorta and is
carried by arteries and capillaries to all parts of the body.
• As it meets cells, it gives up its oxygen and takes on waste
carbon dioxide.
• This blood returns to the heart via veins.
40 - Lesson 2 – How do cells work together?
46 – The Organism
An organism is a complete living thing that relies
on cells for life functions.
What makes up an organism:
Groups of cells
Two or more tissues
All organs
All organ systems
Every human cell needs oxygen and nutrients and
needs to get rid of carbon dioxide and other
chemicals it can’t use.
All the systems help one another work. No system
or organ can work well alone.
Humans are complex multicellular organisms.
List in order the levels of
organization in the human body
•
•
•
•
Cells
Tissues
Organs
Organ Systems
Lesson 2 Review
• Complete numbers 1 and 3-6 as a group.
• I will come around and stamp answer that are
correct, all must have the same answer as that
on the paper I stamp.
50 - Lesson 3 – How Do Cells Reproduce?
50 – How Organisms Grow
Asexual Reproduction-offspring of a single-cell
gets all of its traits.
Fertilization is where an egg cell and a sperm cell
unite to form a single cell. The single cell then
divides until an embryo is formed.
As the cell grows, tissue is made to form organs
and organ systems.
Plants reproduce in a similar way. They form
embryo’s inside the seeds. It doesn’t grow until
conditions are right (weather).
DNA controls your genes. They carry all the
information for how you look, how you grow and
how your body functions.
What happens within a fertilized
egg, from the time it is a single cell
to the time it forms tissues?
• It begins as a single cell that divides and
becomes two cells.
• Thos two cells divide and there are four
cells.
• Cell division continues until cells become
specialized and form tissues.
50 - Lesson 3 – How Do Cells Reproduce?
52 – Mitosis
Body cells are not involved in
producing offspring, but
reproductive cells are.
Body cells make more body cells by
mitosis.
Mitosis has 6 stages.
After mitosis, the two new cells
have the same number of
chromosomes as the starting cell.
50 - Lesson 3 – How Do Cells Reproduce?
The 6 stages of Mitosis:
52 – Mitosis
1. Each chromosome duplicates itself. They are
connected at their centers and bunched inside the
nucleus.
2. Chromosomes become rod-shaped. Nucleus
membrane dissolves and chromosomes go into the
cytoplasm.
3. Long fibers attach to each chromosome pair to help
position the chromosomes in the center of the dividing
cell.
4. Two copies of each chromosome separate and move to
opposite ends of the cell.
5. The fibers break down, chromosomes uncoil and
nuclear membrane forms around each set of
choromosomes.
6. The cell then divides, forming two new cells. Mitosis is
complete.
What has to happen before a cell
can divide?
• The chromosomes must be duplicated.
50 - Lesson 3 – How Do Cells Reproduce?
54 - Meiosis
Reproductive cells are produced by Meiosis and
are responsible for reproduction in plants and
animals.
Before cells divide in Meiosis, the chromosomes
are copied.
Each group then separates and the two
chromosomes move to opposite sides of the cell
and then divide. Each new cell has half of the
chromosomes of the original cell, but has 2
copies of each.
Each cell divides again and move to opposite sides
of the cell. Each of the 4 new cell has ½ the
chromosomes of the original cell.
How does Meiosis make four cells
with 23 chromosomes from one cell
with 46 chromosomes?
It makes copies of its chromosomes first;
then it divides into two cells, each with 46
chromosomes. Then these cells divide
into two more cells, each with 23
chromosomes.
50 - Lesson 3 – How Do Cells Reproduce?
56 – Genetic Variations in Organisms
Asexual reproduction occurs through mitosis. Cells
that are produced have genetic material
identical to their original cell. Which means,
there is no genetic difference between a parent
organism and its offspring.
Sexual reproduction has genetic differences. This
is a result of Meiosis. When a sperm and egg
unite, they produce an organism with unique
genetic makeup…it has only ½ its genes from
each parent.
Which part of meiosis makes it
possible for offspring to vary?
When chromosomes from the parents come
together, they split up randomly. Some
chromosomes may exchange DNA with
another. These steps allow for genetic
variation.
Lesson 3 Review
• Complete numbers 2 and 4-6 as a group.
• I will come around and stamp answer that are
correct, all must have the same answer as that
on the paper I stamp.
• When finished, illustrate an example of mitosis
and meiosis.
What are some traits that the Zebras on this page have?
• Zebras are long-lived animals that move quickly for their
large size and have teeth built for grinding and cropping
grass. Zebras have horse like bodies, but their manes are
made of short, erect hair, their tails are tufted at the tip and
their coats are striped.
Did you know:
Zebras have black skin under their stripes. Each
zebra has its own stripe pattern much like each
human’s fingerprints. The stripes are inherited
traits.
How are traits Inherited?
What are some human physical traits?
59-Lesson 4 - How Are Traits Inherited?
60-Mendel’s Experiment
Mendel observed and studied peas, plants
and wildlife to find out how traits are passed
on from generation to generation.
He chose pea plants because he could
control how they were fertilized and they are
distinctive.
Mendel cross-pollinated pea plants for many
years and recorded his observations.
Mendel is considered the “father of genetics
Exit Ticket
Please include:
One thing you learned today
One thing you still want to know
Lesson 4 - How Are Traits Inherited?
62 – Dominant and Recessive Factors
Traits of the first generation had only one kind
of trait. The traits of their offspring,
always had a ratio of 3:1.
One factor stays hidden in the first generation,
but seen in the second generation.
Some factors are stronger-dominant.
Others are weaker-recessive.
If an offspring has either 1 or 2 dominant
factors, the trait will show up.
A trait with a recessive factor will only show up
if you have two of those recessive
factors.
TT=T
Tt=T
tt=t
Brown Eyed or Blue Eyed?
• One parent has Brown eyes
• One parent has Blue eyes
• Brown is the dominant color
• Choose two cards to see what
color of eyes you would have if
you were their child.
What caused Mendel to conclude
that the factor for tallness is
dominant?
Because the tall plant showed up three times
as often as the short plant in the second
generation.
Lesson 4 - How Are Traits Inherited?
64 – Genes and Inheritance
There are about 35,000 genes on human DNA
Genes from different parents combine
randomly through sexual reproduction. That is
why there are many possible variations in
offspring.
Traits are limited to appearance. playing
sports, painting, singing, writing, personality,
etc.
These traits can skip generations of offspring.
Example: My grandparents can draw, my parents can’t, my sister and I can!
Lesson 4 Review
• Complete numbers 1 and 3-6 as a group.
• I will roll the dice at the end of 30 minutes to see
how we will be grading our papers!
• When finished, illustrate an example of mitosis
and meiosis.