Transcript Quick Review

Quick Review:
• The nucleus controls
most cell processes and
contains nearly all the
cell’s DNA.
•The nucleus is
surrounded by a nuclear
envelope.
•Most nuclei contain a
small dense region called
the nucleolus where the
assembly of ribosomes
takes place.
Questions:
1. Where is the genetic material located in a eukaryotic cell?
2. Which type of organelle assembles proteins?
3. What structures do plant cells have that animal cells do not?
Std. 7 1c
Quick Review:
• Most cells get energy
from the Sun or from
food molecules
• Mitochondria are
organelles that convert
the chemical energy
stored in food into
compounds that are more
convenient for the cell to
use.
Questions:
1. Do animal cells contain chloroplast? Explain
• Chloroplasts are
organelles that capture
energy from sunlight to
convert carbon dioxide
and water into oxygen
and sugars.
2. What two reactions take place inside the chloroplasts?
Std. 7 1d
Quick Review:
• During the cell cycle, a
cell grows and prepares
for division. It divides to
form two identical
daughter cells, each of
which then begins the cell
cycle again.
• All organisms begin their
lifer cycles as a single
cell.
Questions:
1. What is DNA replication? During which stage of the
cell cycle does it occur?
2. During which phase of mitosis do the
chromosomes line up at the center of the cell?
3. What occurs during cytokinesis?
• Most unicellular
organisms reproduce
asexually by a form of
mitosis called binary
fission. In multicellular
organisms, successive
generations of embryonic
cells form by cell division.
Std. 7 1e
Quick Review:
•Atoms are the basic
building clocks of all cells.
• The most common
elements in living things
are carbon, oxygen,
hydrogen, and nitrogen.
Trace elements such as
calcium, iron, potassium,
phosphorus, sodium, and
sulfur are also important.
Questions:
• Water molecules are
essential for most
chemical reactions that
take place within living
cells.
1. Which two gases found in the atmosphere are needed by most living things?
2. What property of water molecules enables most chemicals important for life
to dissolve in water?
Std. 8 6 b.
Quick Review:
• The body needs water
because many of the
body’s processes,
including chemical
reaction, take place in
water.
• Water is needed by
plants for the process of
photosynthesis.
Questions:
1. How do solutions differ from other types of mixtures?
2. How does water’s porperty as a solvent affect the composition of blood,
which is mainly water?
Std. 8 6 c.
Quick Review:
• The cell membrane controls the internal
environment of a cell. Materials can move
through the membrane by diffusion,
osmosis, or active transport.
• The composition of nearly all cell
membranes is a double-layered sheet
called a lipid bilayer.
• Molecules move by diffusion form an area
of higher concentration to an area of lower
concentration.
• Water moves in or out of a cell by
osmosis based on concentration
differences across a cell membrane.
• Active transport moves materials through
a cell membrane against a concentration
Questions:
gradient.
1. What is the function of the cell membrane?
2. What other molecules are found in the cell membrane?
Std. BI 1. a
Quick Review:
• Osmosis is the diffusion of
water through a selectively
permeable membrane.
• Substances diffuse from an
area of higher concentration to
an area of lower concentration.
• Osmosis is one of several
processes that allow cells to
maintain homeostasis.
Questions:
1. How does a cell keep from taking in excess water?
2. Why can some substances pass through a cell membrane and others
cannot?
Std. BI 1 a
Quick Review:
• Cells must move waste
products across the cell
membrane to maintain
homeostasis within the cell.
• Diffusion, osmosis, and active
transport move materials
across the cell membrane.
• Active transport moves
materials against a
concentration gradient and
requires an input of energy from
the cell.
Questions:
1. Name two differences between active transport and diffusion.
Std. BI 1. a
Quick Review:
• Most cells function best within
a narrow range of temperature
and acidity. Extreme changes
may harm cells because they
change the structure of their
proteins.
• Enzymes increase the rate of
reaction by reducing the
activation energy needed to get
the reacting started. Most
enzymes are proteins.
Questions:
• When conditions are too
acidic or too alkaline, enzymes
do not work as well and
reactions are slower than when
the pH is optimal.
1. What happens to the rate of the reaction in the presence of an acid?
2. What happens to the rate fo the reaction when a base is added?
Std. BI 1. b
Quick Review:
• Enzymes are biological
catalysts. They speed up
chemical reactions in cells.
• Substrates bind to the active
site on an enzyme. The active
site and the substrate have
complementary shape. They fit
together like a lock and a key.
• When the reaction is complete
the products of the reaction are
released and the enzyme is
free to start the process again.
Questions:
1. How do enzymes speed up chemical reactions?
2. Where on an enzyme does the reaction take place?
3. What would happen if a cell lacked a key enzyme?
Std. BI 1. b
Quick Review:
• Biologists divide cells into
eukaryotes, which have a
membrane-bound nucleus, and
prokaryotes, which lack a
membrane-bound nucleus.
• Prokaryotes are generally
smaller and simpler than
eukaryotes. Prokaryotes are
bacteria.
• Eukaryotes contain dozens of
specialized structure and
membranes. Plants, animals,
fungi, and protists are
eukaryotes.
Questions:
1. What invention allowed scientists to discover that living things are made from
cells?
2. What other differences do you see between prokaryotic and eukaryotic cells?
Std. BI 1. c
Quick Review:
Viruses and Cells
Structure
DNA or RNA
core, or
capsid
Cell
membrane,
cytoplasm,
organelles,
nucleus
Reproduction
Only within a host
cell
Independent cell division
either asexually or sexually
Genetic Code
DNA or RNA
Growth and
development
Obtain and
use energy
No
No
Yes
Response
No
Yes
Change over
time
yes
Yes
• A virus has an outer coat of
protein and an inner core
containing either DNA or RNA.
• Viruses reproduce by invading
a living cell and using the host
cell’s machinery to replicate.
DNA
Yes; in multicellular
organisms, cells increase in
number and differentiate.
Questions:
1. How do viruses compare to cells in methods of reproduction?
2. What is one characteristic shared by viruses and cells?
Std. BI 1. c
Quick Review:
• During transcription, RNA
polymerase binds to DNA and
separates the DNA strands.
• RNA polymerase then uses
one strand of DNA as a
template from which
nucleotides are assembled into
a strand of RNA.
• There are three main
differences between RNA and
DNA: the sugar in RNA is
ribose instead of deoxyribose,
RNA is generally single
stranded, and RNA contains
uracil in place of thyamine.
Questions:
1. Where in the cell does transcription take place?
2. What RNA nucleotide sequence would be transcribed from the DNA
sequence ACG?
Std. BI 1. d
Quick Review:
•Some of the proteins
synthesized by the cell are
used within the cell; others are
exported from the cell.
• Proteins that are exported
from the cell are synthesized on
the rough endoplasmic
reticulum.
•The Golgi apparatus modifies,
sorts, and packages proteins
and other materials for export
from the cell.
Questions:
1. Are proteins synthesized in the nucleus or in the cytoplasm of a cell?
2. What are the building blocks of proteins?
Std. BI 1. e
Quick Review:
•During photosynthesis, plants
and some other organisms use
energy from the sun to convert
carbon dioxide and water into
oxygen and sugars, including
glucose.
• The light-dependent reactions
produce oxygen gas and
convert ADP and NADP+ into
the energy carriers ATP and
NADPH.
• The Calvin cycle uses ATP
and NADPH to produce highenergy sugars.
Questions:
1. What is the cycle that produces high-energy sugars during photosynthesis?
2. What are the products of the light-dependent reactions?
3. Where does photosynthesis take place?
Std. BI 1. f
Quick Review:
• Living things get the energy
they need from food.
• Cellular respiration is the
process that releases energy by
breaking down food molecules
in the presence of oxygen.
• Mitochondria are organelles
that convert the chemical
energy stored in food into
compounds that are easier for
the cell to use.
Questions:
1. What does glycolysis break down?
2. What takes place in the mitochondria?
Std. BI 1. g
Quick Review:
• The four basic types of
organic molecules found in all
cells are carbohydrates, lipids,
proteins, and nucleic acids.
• Carbohydrates and lipids are
used by living things for energy
to fuel biological processes.
•Proteins and nucleic acids are
used to build and repair body
parts.
Questions:
1. What are the monomers that make
up each basic type of organic
molecule?
3. What two important kinds of molecules in
all cells are nucleic acids?
2. What two forms of carbohydrates
are made from long chains of
glucose molecules connected in
different arrangements?
Std. BI 1. h
Quick Review:
• Cell membranes contain a
protein called ATP syntase that
spans the membrane.
•As H+ ions pass into the ATP
synthase, it spins. Each time it
rotates, the enzyme grabs a
low-energy ADP and attaches a
phosphate forming high energy
ATP.
Questions:
1. What is the role of ATP synthase during cellular respiration?
Std. BI 1. g
Quick Review:
• The cytoskeleton helps the
cell to maintain its shape. It
also is involved in cell
movement.
• The cytoskeleton is made up
of microfilaments and
microtubules.
• Microfilaments are made up of
the proteins actin. Microtubules
are made up of proteins called
tubulins. Microtubules form cilia
and flagella.
Questions:
1. What are two functions of the cytoskeleton?
2. How do organisms, such as paramecia, use cilia to move?
Std. BI 1. j
Quick Review:
• The cytoskeleton helps the
cell to maintain its shape. It
also is involved in cell
movement.
• The cytoskeleton is made up
of microfilaments and
microtubules.
• Microfilaments are made up of
the proteins actin. Microtubules
are made up of proteins called
tubulins. Microtubules form cilia
and flagella.
Questions:
1. What are two functions of the cytoskeleton?
2. How do organisms, such as paramecia, use cilia to move?
Std. BI 1. j