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Unit 4:
Cell Notes
Products and Reactants
• chemical reaction: process that changes one set of
chemicals into another
• reactants: elements or compounds that you start out with
• products: “ “
“
“
“
finish with
REACTANTS
PRODUCT(S)
• How are cell structures adapted to their
functions?
Prokaryotes:
- bacteria cells
- reproduce through
binary fission
- genetic material is
not in nucleus
-Less complex,
usually smaller
Both:
- are cells
-Contain genetic
information
Eukaryote:
-plant, animal,
and protist cells
- reproduce
through mitosis
and meiosis
-Genetic
material is in
nucleus
- more complex,
often larger
• Organelles = “little organs”, make up the
cell
– Nucleus – contains DNA
– Ribosomes – make proteins
– Endoplasmic reticulum – where lipid parts of
the cell membrane are assembled, along with
proteins and other materials that are exported
from the cell
– Other organelles: golgi apparatus, lysosomes,
mitochondria, etc…
Chromosomes
– threadlike
structures that
consist of DNA;
contains
genetic
information
Cell Membrane
• regulates what enters and leaves
the cell; like a wall with guarded
doors
• double layer of lipids called a “lipid
bilayer” (the wall) with proteins that
is semipermeable – only allows
certain things through (like a
guarded door)
• lipids: macromolecules that include
fats, oils, and waxes; hydrophobic
• proteins: macromolecule
that contains nitrogen, is used
to form bones and muscles,
regulates cell processes
SOLUTE (like sugar)
CARRIER PROTEIN
LIPIDS
http://www.johnkyrk.com/cellmembrane.html
Active Transport
• movement against concentration gradient
• requires energy
• endocytosis : the process of taking
material into the cell by means of
infoldings of the cell membrane
Passive Transport
- the passage of substances across cell membranes
without input of energy
– diffusion: particles move from an area where they
are more concentrated (closer together) to where
they are less concentrated. When the
concentration of the solute is the same throughout a
system, the system has reached equilibrium
– osmosis: membrane allows water through, but not
the solute
• solute: a dissolved substance
• Osmotic pressure
– hypertonic - solution has higher solute concentration
than the cell; greater pressure on the outside
– isotonic – the concentration of solutes is the same
inside and outside of the cell; equal pressure on the
inside and outside of the cell
– hypotonic – solution has a lower solute
concentration than the cell; greater pressure on the
inside of the cell than the outside
Analogy: Balloon and membrane
• membrane – the sides of the balloon
• concentration – the amount of air on the
inside of the balloon
• what type of osmotic pressure would exist
if you were able to blow so much air into
the balloon that it popped?
• Why does frozen fruit become mushy after it
melts?
• what happens to water when it freezes?
• The water expands, lysing (bursting) the cell
• cell swells and wall bursts
Why do athletes need electrolytes?
• all muscle cells use calcium and sodium to
close or contract the cell, and magnesium
and potassium to relax the cell
• when the sodium level dips too low, the
kidneys are stimulated to produce more
urine, which lowers the amount of water in
the bood
• when sodium levels get too high, thirst
develops
Why do people gain weight from
eating salty food?
• in a normal cell, there will be the same
concentration of solute, in this case salt, on the
inside and outside of the cell
• if you are a person who eats too much salty
food, the extra salt will go into your cells
• salt sucks water towards itself, so water will be
sucked into the cell, where the salt is
• the cell will become swollen (hypotonic)
• you will have extra water in your body, and gain
weight from the excess water
• Tissue – a group of similar cells that
perform a particular function
Cells  tissues  organs  organ systems
Section 2
key terms from chapters 8, 9, and 11
• How do plants and other organisms
capture energy from the sun?
• How do organisms obtain energy?
CHLOROPLAST
Photosynthesis = plants use sunlight energy
to convert water and carbon dioxide into
high-energy carbohydrates -sugars and
starches- and oxygen, a waste product
6CO2 + 6H2O  (light energy)  C6H12O6 +6O2
Photosynthesis
• has two parts:
– Light reactions
– Calvin cycle
• Takes place in:
– chloroplasts
• Results in:
– Sugar and oxygen
6 CO2 + 6 H20 + light → C6H12O6 +6O2
• Thylakoids –
membrane where
the light
reactions take
place
• Grana – stack of
thylakoids
• Light reactions:
energy from
sunlight changes
ADP to ATP, and
splits H2O
What is ATP?
Adenosine triphosphate (ATP) = one of the
principal chemical compounds that cells use to
store and release energy;
- is like a fully charged battery
Calvin cycle
Photosynthesis &
the- starts with CO2, H
and ATP (energy)
photosynthesis
- Energy from ATP is
stored in sugar
(C6H12O6)
Light
Reactions
Calvin
Cycle
C6H12O6
Cellular respiration
- Breaks down sugar in the presence of
oxygen
- Results in carbon dioxide, water, and
energy
- The opposite of photosynthesis
C6H12O6 + 6O2  6CO2 +6H2O + energy
Q: What is the purpose of ATP and
ADP + P?
A: To carry energy from the sun to the calvin
cycle where it is stored in the sugar’s
chemical bonds.
C6H12O6 + 6O2  6CO2 +6H2O + energy
Cellular respiration usually uses
oxygen. In cases where it does not
use oxygen, it is called fermentation,
and is said to be anaerobic, or without
oxygen. This is why a cork is put into a
bottle of wine – to keep oxygen out so
fermentation will take place
Aerobic – requires oxygen --^ (ex: cellular
respiration)
Anaerobic – does not use oxygen (ex:
fermentation)
Section 3
How does a cell produce a
new cell?
Fluorescent In-Situ Hybridization (FISH) identification of human chromosomes
Chromosome
- replicated
DNA that is
wrapped around
histone proteins
and coiled up
- replicates and
condenses
before
mitosis/meiosis
Chromosome Numbers
Autosomes
- Contain most of the genetic information; all
chromosomes that are not sex chromosomes
- Humans have 22 pairs of autosomes,
Sex Chromosomes
- Genetic information that determines gender of
an organism
- Humans have 1 pair of sex chromosomes.
- females - XX
- males - XY
2n Chromosomes
Honeybee (female) – 32 Adder’s Tongue Fern - 1262
Human - 46
Cat - 38
Common Frog - 26
Maize - 20
Organisms
more chromosomes
Does more with
chromosomes
mean a biggerare not
necessarily
more complex
or more complicated
organism?
Karyotype
A photomicrograph
of the chromosomes
in a normal dividing
cell found in a
human.
Does this karyotype
appear to be male
or female?
karyotyping
Eukaryotic cell division
First, chromosomes are replicated (copied)
Mitosis
- One division, produces 2 identical daughter cells
- Diploid (full set of chromosomes)
- Occurs in body cells, or somatic cells
- Growth, replacement, repair
Meiosis
- Two divisions, produces 4 cells
- Haploid (one of each chromosome pair)
- Occurs in gametes (reproductive cells)
- Gametes from male and female combine to form a
http://www.johnkyrk.com/mitosis.html
diploid zygote
Gametes
• gametes - the only
cells that go through
meiosis.
• Sexual reproduction –
the production of
offspring through meiosis
and the union of a sperm
and an egg
• Zygote – a male gamete
and a female gamete
combine to form a new
organism; each
contributes half the
genetic information
Cancer
the uncontrolled
growth of cells
• Mistake at cell
checkpoint
– Metastasis – the
spread of cancer
• Cells break off and
travel
Cancerous moles (melanoma)
http://oralcancerfoundation.org/facts/metastasis.htm