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Cells and Tissues
What is it that makes you you?
What is the biggest organelle?
• The nucleus
– The control center for the cell
– Contains DNA
• Contains the message that
makes proteins
• Proteins run the cell.
– Contains the organelle=
nucleolus
• Nucleolus makes RNA that
carries out DNA’s
instructions.
What surrounds the nucleus?
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•
•
•
The Phospholipid membrane
Two membranes.
Keeps DNA in
Only RNA can leave
What are the names of DNA?
• Chromatin: Unwound DNA
• Chromosomes: Tightly wound DNA
What surrounds the cell?
• The Plasma Membrane. Made out of
Phospholipids.
• May have cilia or microvilli around the cell.
• Microvilli are in the back of your throat
(filter air) and in your intestine (absorb
food). Pg.389 +419
What is in the cell?
• Most of the cell is full of Cytoplasm.
– Cytoplasm: Gel like fluid where most of the
cells chemical reactions take place.
• Organelles: Mini cell organs that carry out
specific job functions for the cell.
Cells Alive
Overview of Cell Parts
What are the major organelles?
• Ribosomes: rRNA. Where proteins are
made. Usually on the rough ER.
• Endoplasmic Reticulum:
– rough ER close to the nucleus, where proteins
are made
– Smooth ER makes lipids. No rRNA present.
• Golgi Apparatus: Ships proteins and
lipids.
More organelles…
• Lysosomes: SOS. Contain digestive
enzymes. Kill invaders and worn out cell
parts.
• Mitochondria: Power house of the cell.
Makes ATP (Body runs on ATP energy.)
• Cytoskeleton: Skeleton of the cell. Shape
• Centrioles: Move Chromosomes during
cell division.
Membrane Transport
Pg. 46
What kinds of fluids pass through
the cell membrane?
• Solution: homogeneous mixture of two or
more things
– Solvent: Bigger word, bigger thing
– Solute: Smaller word, smaller thing
• Intracellular fluid: fluid in the cell that
contains gasses, nutrients, salts, & water
• Interstitial fluid: bathes the outside of our
cells.
Why is the plasma membrane
selectively permeable?
• Works as a barrier. Only allows certain
things in or out of the cell.
• Means of protection.
• Cells that can not do this are dead or
damaged.
What are the two forms of cell
transport?
• Active Transport: uses energy (ATP) to
move molecules against the concentration
gradient or to move large things.
• Passive Transport: uses NO energy to
move molecules with the concentration
gradient.
What types of Passive transport
does the body use?
• Diffusion: When molecules move from
high to low or with the concentration
gradient.
– Perfume, food coloring, etc. all do this.
• Osmosis: a specialized form of diffusion
which moves water from high to low across
the plasma membrane.
What types of Passive transport
does the body use?
• Facilitated Diffusion: Uses carrier
proteins to move substances without energy
with the concentration gradient.
• Filtration: water and solutes are forced
through a plasma membrane. Happens in
the Kidneys.
What types of Active transport do you use?
• Solute Pumping: Require protein carriers
and energy to move sugars, Amino Acids,
and ions against the concentration gradient.
(Sodium Potassium pump used in Nerve cells)
More Active Transport…
• Bulk Transport: Substances too big to
pass through the plasma membrane.
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–
–
–
Exocytosis: Large things exit the cells
Endocytosis: Large things enter the cell
Phagocytosis: Cells that eat- white blood cell
Pinocytosis: Cells drink- intestine and kidneys
Types of Solutions: Pg 60
• Isotonic Solution: Same tonicity inside and
outside the cell. Cell stays the same size.
• Hypertonic Solution: Higher tonicity
outside the cell. Cell shrinks.
• Hypotonic Solution: Lower tonicity outside
the cell. Cell swells and “POPS”
Chromosomes and Mitosis
Pg. 63
Two different Cell Divisions
• Meiosis- produces gametes or sex cells.
New cells are different from the original
cell.
• Mitosis- produces new body cells-like your
toes. New cells are identical to original cell.
DNA in all of its fine forms:
• Chromosomes: Tightly wound DNA.
Resemble an X because two chromatids are
held together.- Supercoiled.
• Centromere holds the chromosomes (Two
sister Chromatids) together.
• Chromatid: A single tightly wound strand
of DNA.
Homologous Chromosomes
And last but not least…
• DNA is your genetic information. In the
shape of a double helix. The nucleotide
pairs are: (Hydrogen bonds)
– Adenine= Thymine
– Cytosine: Guanine
• DNA is broken into segments called genes
which code for proteins.
• Genes give you your physical
characteristics.
It DNA the final say?
• Epigenetics may play a role.
Epigenetic Effect
On DNA
Epigenetic
Movie
Before Eukaryotic Cells
Divide…
• Its chromosomes are replicated.
• Happens through the process of DNA
Replication. DNA Replication pg.68
• DNA needs enzymes (protein) to copy or
replicate itself.
• Double helix unwinds using DNA Helicase.
• DNA Helicase breaks the hydrogen bonds.
• Where the DNA breaks apart is called the
replication fork. DNA polymerase (another
enzyme) adds nucleotides at this point.
How many Chromosomes do
humans have?
• Each somatic cell or body cell has two
copies of 23 chromosomes.
• One copy of the chromosomes (sex cells or
gametes) have 23 chromosomes and are
called haploid or n = 23.
• Two copies of the chromosomes (somatic
cells) have 2n = 46.
There are two types of
Chromosomes.
• Autosomal Chromosomes: or autosomes are
not sex chromosomes.
• Sex Chromosomes: determine the sex of the
individual. The male of the species
determines the sex of the offspring. Women
only have one X chromosome. Males have
an X or a Y.
• XX is a girl
• XY is a boy
Karyotypes: Pictures of your
DNA.
• Why do we take pictures? To find mistakes
.
The 5 stages of the Cell Cycle
6-2
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G1: Cell Growth and Metabolism
S: DNA is copied
G2: Cell prepares for division.
Mitosis: Nucleus divides, cell parts
separate.
• Cytokinesis: Cytoplasm divides
When control of the Cell cycle is
lost: Cancer is the outcome.
• Cancer: uncontrolled cell division or death.
• Read pg 127: Normal cells become
cancerous.
Hit the Cancer Biology
Documentary Link
Mitosis The Basic Steps:6:3
• Prophase: DNA forms chromosomes.
Nuclear envelope disappears. In Animals
spindle fibers form.
• Metaphase: Chromosomes move to the
center of the cell- pulled by spindle fibers.
• Anaphase: Chromosomes are separated into
chromatids. Spindles shorten pulling
chromatids to opposite ends of the cell.
• Telophase: Nucleus reforms. Chromatids
turn back into Chromatin. Spindles
The Jazzy
disappear.
Version of
Mitosis
After Mitosis
• Cytokinesis: Cytoplasm divides in half.
• Animals: The plasma membrane pinches in
half= Furrow.
• Plants: A cell wall grows between the two
new cells. Cell Plate.
Cell Cycle
Movie/
Game
Meiosis
.
Meiosis: The making of gametes
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One cell eventually creates four cells
Each cell is different from the parent cell
Haploid
Meiosis goes through cell division twice
The Stages of Meiosis
• Prophase 1: Chromosomes are made
and the nucleus membrane disappears.
• Homologous Chromosomes pair and attach
by centromeres.
• Crossing-over occurs. Cross over is the
process of homologous chromosomes
breaking off and exchanging parts.
– This process is responsible for making you
unique!
Meiosis Continued
• Metaphase 1
Homologous
chromosomes are
pulled by spindle
fibers to the middle of
the cell. (Two pair of
homologous
chromosomes are
together.)
• Anaphase 1
• Pair of Homologous
chromosomes
separate. Spindle
fibers attach to a
centromere to guide
homologous
chromosomes to
opposite ends of the
cell.
Meiosis Continued
• Telophase 1
• Two cells have
been made. We
• Homologous
need 4.
chromosomes are at
opposite ends of the • Here ends the first
cell. Cytokinesis
cell division.
occurs.
• Ready for part two?
Meiosis- Part 2
• Prophase II
• Metaphase II
• New spindle fibers • Chromosomes line
form around
up in the middle (or
homologous
equator) of the cell.
chromosomes.
Nucleus disappears.
And finally…Meiosis ends
• Anaphase II
• The spindle fibers
pull the
homologous
chromosomes apart.
Chromatids move
to opposite ends of
the cell.
• Telophase II
• A new nucleus is
formed. Spindle fibers
dissolve.
• Cytokinesis occurs.
• Four cells, genetically
different from the
parent cell have been
made.
Why does Meiosis create
genetic variation?
• Crossing over. Mixes up the traits on each
chromosome.
• Independent assortment. You have 46
chromatids. ½ go to each new cell in Meiosis
1 and again in Meiosis II. No one knows
which chromatids will go to which cell.
• Random Fertilization. Which egg and which
sperm will meet? = a greater genetic
variability.
Making Gametes:
Different for different sexes.
• Sperm Formation
• Spermatogenesis
• One diploid germ cell
makes four haploid
sperm cells.
• Occurs in the testis
throughout the males
Third Link
adult life
• Egg formation: Ovum
• Oogenesis
• One diploid germ cell
makes one egg and three
polar bodies.
• Egg must provide the food
for the zygote (fertilized
egg)
• Made in ovaries, most
before birth
Comparison of
OOGENESIS
&
SPERMATOGENISIS
Sexual Reproduction: Two
parents.
• Offspring is genetically different from
parents.
• Great for environmental change. Easy to
evolve.
• Meiosis can better repair damaged DNA
How Proteins are Made
Pgs. 60-61
The Basic Process of Making
Protein
• DNA (In the Nucleus) is Transcribed into
mRNA. (Transcription)
• RNA brings the message to the Rough ER
where its Translated into a protein.
(Translation)
The Details: RNA
(Ribonucleic Acid)
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There are three types of RNA
mRNA (messenger RNA)
rRNA (Ribosomal RNA)
tRNA (Transfer RNA)
RNA is Single Stranded, sugar is RIBOSE
The Nitrogen bases for RNA are…
– Adenine bonds to Uracil
– Cytosine bonds to Guanine
The Story
• DNA is stuck in the nucleus.
• RNA is made in the nucleolus.
• mRNA transcribes or re-writes DNA’s code
in RNA and leaves the nucleus through
nuclear pores.
• mRNA brings the message to the ribosome
also known as rRNA.
The fairy tale continues Fig 10-5
• Once mRNA is hooked onto the rRNA it
needs the right amino acids to make a
protein.
– Remember 50 or more A.Acids make a Protein!
• tRNA carries amino acids to the rRNA and
hooks them onto the correct mRNA codon.
– A codon is a three nucleotide sequence (AUG)
How does the story end?
• When the stop codon is reached the Amino
Acid chain falls off and rolls into a ball and
becomes a protein.
• mRNA goes back to the nucleus to be
reused.
• rRNA stays on the Endoplasmic Reticulum
waiting for the next job.
• tRNA picks up new Amino Acids for the
next job.
Overview Movie
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