Transcript Biology - Shelbyville Central Schools

Biology
Bio- = life
-ology = the study of
Organisms – living things
Cell – smallest unit of an organism that can carry
on life functions
Prokaryotic cell – cell with NO nucleus
example: bacteria
Eukaryotic cell – cell with a nucleus
example: all organisms EXCEPT bacteria
Unicellular – an organism made of only one cell
examples: euglena, amoeba, paramecium
Multicellular – an organism made of many cells
examples: animals, trees, mushrooms
Antonie van Leeuwenhoek – made a simple
microscope with a glass bead that could magnify
up to 270 times
Robert Hooke - discovered the “cell”
- looked at a piece of cork
- said the cells look like little boxes
CELL THEORY
1. All organisms have one or more cells
2. All cells come from cells (DIVIDE)
3. Cells are basic units of life
Matthias Schleiden – all plants are made of cells
Theodor Schwann – all animals are made of cells
Rudolph Virchow – cells divide to make new cells
Cell Parts and Function
Nucleus – control center, directs activities
of the cell
Cytoplasm – gel-like material inside cell
Cell Wall – supports and protects plant cell
Cell Membrane – protective layer, allows
certain material in and out of cell
Chloroplast – green structure in plant cells,
allows plants to make their own food
Mitochondria – where energy in food is
stored then released; POWERHOUSE
Ribosomes – makes proteins
Endoplasmic reticulum – folded membrane,
moves materials in cell
Vacuole –storage for food, water, waste
Lysosome – breaks down food, waste, and
worn out cell parts
Golgi Body – packages proteins
Moving Cellular Material
Cell Membrane –allows certain material
in and out of cell
Selectively permeable – selects what
can enter and leave based on size
Passive Transport Systems DO NOT use
energy to move substances through
the cell
3 Types of Passive Transport Systems
1. Diffusion – random movement of
molecules from higher concentration to
lower concentration until they reach
equilibrium (ex. Vanilla in balloon)
2. Osmosis – diffusion of water through a cell
membrane (ex. Carrot in salt water)
3. Facilitated Diffusion – transport proteins
help large molecules, like glucose, enter the
cell (ex. Drive through window of
McDonalds)
Active Transport System –
energy is needed to
move a substance
through membrane, like
root cells needing
minerals from soil (ex.
Going back into a
stadium after the game)
Endocytosis – cell process that takes in a
substance by surrounding it. (ex. How amoeba
takes in food)
Exocytosis – contents of a vesicle can be
released. (ex. Cells in stomach release
chemicals to help digest food)
Cell Membrane Transport
A. Diffusion and Osmosis
B. Facilitated Diffusion
C. Active Transport
D. Endocytosis
E. Exocytosis
Energy for Life
Metabolism – Organisms use energy to carry out
activities of life, like making food, breaking
down food, building cells, moving materials in
and out of cells.
The total of all chemical reactions in an organism.
Enzyme – causes a change and can be used again
Producers – organisms that can make their own food
Consumers – organisms that cannot make their own
food
Photosynthesis – process of changing light energy
into chemical energy (use light to make sugars)
START: carbon dioxide, water, light energy
END: glucose sugar, oxygen
Happens in
chlorophyll
Cellular Respiration – process that breaks down
food molecules into simpler substances and
releases energy (split glucose using oxygen)
START: glucose sugar, oxygen
END: carbon dioxide, water, energy
C6H12O6+6O2
6CO2+6H2O + energy
Happens in mitochondria
Click link below
http://www.pbs.org/wgbh/nova/methuselah/phot_flash.html
Fermentation – process of releasing stored
energy without the use of oxygen.
enzyme
C6H12O6
C2H5OH + 2CO2
yeast cells ferment into ethanol alcohol and carbon
dioxide
muscle cells ferment into lactic acid and energy
C6H12O6
2C3H6O3 + energy
Cell Division and Mitosis
Why do cells divide?
Many organisms start as one cell.
That cell divides and become two, two becomes four,
four becomes eight, and so on.
Multi-cellular organisms grow because cell division
increases the number of cells.
Even after growth stops, cell division is important.
Every day, billions of red blood cells wear out and are
replaced.
During a few seconds, bone marrow can produce six
million red blood cells.
Cell Cycle
Organisms have a life cycle.
Cells also have a life cycle.
Onion Root
Tip
Onion
Root Tip
Interphase (growth and development)
1. Chromosomes double
Prophase
Mitosis
1. Centrioles divide move toward poles
2. Nuclear membrane disappears
3. Nucleolus disappears
4. Chromosomes appear
5. Spindle fibers appear
Metaphase
1. Chromosomes line up across equator
Anaphase
1. Chromosomes move toward poles
Telophase (cytoplasm begins to divide)
1. Chromosomes disappear
2. Spindle fibers disappear
3. Nuclear membrane appears
4. Nucleolus appears
Cytokinesis – cytoplasm divides
Plant cells – cell plate (forms new cell wall)
Animal cells – furrow (forms new cell membrane)
Plant cell
Animal cell
Mitosis Movie
Click to
play movie
Mitosis in plant cell
Cell division in animal cells and plant cells is similar,
but plant cells do not have centrioles and animal
cells do not form cell walls.
Organisms use cell division to grow, to replace cells,
and for asexual reproduction.
Asexual reproduction produces organisms with DNA
identical to the parent’s DNA.
Fission, budding, and regeneration can be used for
asexual reproduction.
Fission
During fission, an organism whose cells do not
contain a nucleus copies its genetic material
and then divides into two identical organisms.
Example: Bacteria uses fission to reproduce
Regeneration
Regeneration is the process that uses cell
division to regrow body parts.
Examples: sponges, planaria, sea stars
Budding
• When the bud on the adult becomes large
enough, it breaks away to live on its own
Examples: hydra
Meiosis and Sexual Reproduction
• Sexual reproduction results when an egg and sperm
join. This event is called fertilization, and the cell
that forms is called the zygote.
• Meiosis occurs in the reproductive organs,
producing four haploid sex cells.
• During meiosis, two divisions of the nucleus occur.
• Meiosis ensures that offspring produced by
fertilization have the same number of chromosomes
as their parents.
Sexual reproduction – type of reproduction when
two sex cells come together (egg and sperm)
Sperm – sex cells formed in the male reproductive organs
Egg – sex cells formed in the female reproductive organs
Fertiliztion – joining of an egg and sperm
Zygote – cell that is formed due to fertilization (diploid)
Diploid – when cells have pairs of similar chromosomes
Haploid – when cells do NOT have pairs of chromosomes
Meiosis – produces haploid sex cells
23
Human
46
23
Types of Human Cells
Diploid
Haploid
# of
chromosomes
46
23
Process that
produces them
Mitosis
Meiosis
Brain cells, skin
cells, bone cells
Egg cells and
sperm cells
Examples
Meiosis Movie
Click to
play movie
Meiosis I
Prophase I
Prophase I is similar to
prophase in Mitosis
In Prophase I, each
duplicated chromosome
comes near its similar
duplicated mate
Meiosis I
Metaphase I
In metaphase I, the pairs of
duplicated chromosomes line
up in the center of the cell.
The centromere of
each chromatid pair
becomes attached to
one spindle fiber, so
the chromatids do not
separate in anaphase I.
Meiosis I
Anaphase I
In anaphase I, the two
pairs of chromatids of
each similar pair move
away from each other
to opposite ends of the
cell.
Meiosis I
Telophase I
In telophase I, the
cytoplasm divides, and
two new cells form.
Meiosis II
Prophase II
In prophase II, the
duplicated chromosomes
and spindle fibers
reappear in each new
cell.
Meiosis II
Metaphase II
In metaphase II, the
duplicated chromosomes
move to the center of the
cell.
Meiosis II
Anaphase II
The centromere divides
during anaphase II, and
the chromatids separate
and move to opposite
ends of the cell.
Meiosis II
Telophase II
As telophase II begins,
the spindle fibers
disappear, and a nuclear
membrane forms around
the chromosomes at each
end of the cell.
Meiosis Summary
DNA
DNA
Double Helix – twisted ladder
Discovering DNA
Rosalind Franklin – 1952
discovered that DNA is two
chains of molecules in spiral
form.
X-Ray diffraction of DNA
James Watson and Francis Crick
1953
made a model of DNA
DNA = deoxyribonucleic acid
Nucleotides (3 parts)
1. SUGAR – deoxyribose sugar C5H10O4
2. BASE - Adenine
- Guanine
- Cytosine
- Thymine
3. PHOSPHORIC ACID - H3PO4
P
S
B
Double helix = twisted ladder shape of DNA
Sides of the ladder = phosphoric acid and sugar
Rungs of the ladder = nitrogen base pairs
A–T
C–G
Bases are held together by hydrogen bond
When chromosomes are duplicated
before mitosis or meiosis, the amount
of DNA in the nucleus is doubled.
The two sides of DNA unwind and separate.
DNA Duplication
1. Uncoils
2. Hydrogen bond breaks (unzips)
3. New nucleotides replace old (pair up)
RNA = ribonucleic acid
Sugar – ribose sugar C5H10O5
RNA looks like half of a ladder
4 bases – G,C,A, and U for uracil
Different types of RNA
tRNA – transfer RNA
mRNA – messenger RNA
rRNA – ribosomal RNA
How DNA and RNA are different
DNA
RNA
Deoxyribose sugar
Ribose sugar
Thymine
Uracil
Double stranded
Single stranded
Found in nucleus
Found in nucleus and
cytoplasm
Click for DNA animation
http://207.207.4.198/pub/flash/24/menu.swf
GENES
• Most of your characteristics, such as the color of
your hair, your height, and even how things taste to
you, depend on the kinds of proteins your cells
make.
• DNA in your cells stores the instructions for making
these proteins.
• Proteins build cells and tissues or work as enzymes.
• The instructions for making a specific protein are
found in a gene which is a section of DNA on a
chromosome.
GENES
• Each chromosome
contains hundreds of
genes.
• Proteins are made of
chains of hundreds or
thousands of amino acids.
• The gene determines the
order of amino acids in a
protein.
• Changing the order of the
amino acids makes a
different protein.
Protein Synthesis (making proteins)
•
Genes are found in the nucleus, but proteins are
made on ribosomes in cytoplasm.
1. Transcription – DNA gives information to mRNA (code)
mRNA is made from DNA in the nucleus
2. mRNA goes through nuclear membrane to cytoplasm and
attaches to ribosome
Translation
3. tRNA attach to amino acid
4. tRNA brings amino acid to ribosome and plugs into mRNA
* peptide bond holds the two amino acids together
5. When all amino acids are lined up a PROTEIN is formed
Protein Synthesis link
http://207.207.4.198/pub/flash/26/transmenu_
s.swf