Cell Biology
California Biology/Life Science Standard 7 1 .c
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 begins.
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?
1. In the nucleus 2. Ribosomes 3. A cell wall, a vacuole, and chloroplasts
Cell Biology
California Biology/Life Science Standard 7 1.d
Quick Review
Most cells get energy either 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.
Chloroplasts are organelles that capture energy from sunlight to convert carbon dioxide and water into oxygen and sugars.
Questions
1.Do animal cells contain chloroplasts? Explain your
answer.
2.What two reactions take place inside the
chloroplasts?
1. No, animals do not carry out photosynthesis.2. The light-dependent reactions and the Calvin cycle
Cell Biology
California Biology/Life Science Standard 7 1.e
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 cycle again.
All organisms begin their life cycles as a single cell.
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.
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 across the center of the cell?
3. What occurs during cytokinesis?
1. The process of copying the cell’s DNA; interphase 2. Metaphase 3. The cytoplasm divides, distributing the organelles
between the two daughter cells.
Cell Biology
California Biology/Life Science Standard 8 6.b
Quick Review
Atoms and molecules are the basic building blocks 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.
Water molecules are essential for most chemical reactions that take place within living cells.
Questions
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?
1. Oxygen and carbon dioxide2. They are polar.
Cell Biology
California Biology/Life Science Standard 8 6.c
Quick Review
The body needs water because many of the body's processes, including chemical reactions, 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 property as a solvent affect the composition of blood, which is mainly water?
1.Their components are evenly distributed.
2.Because it is mostly water, blood can transport dissolved molecules (such as glucose) and ions (such as sodium), which are essential for cells to perform their functions.
Cell Biology
California Biology/Life Science Standard BI 1.a
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 from 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 gradient.
Questions
1.What is the function of the cell membrane?
2.What other molecules are found in the cell
membrane?
1.The cell membrane regulates what enters and leaves the cell and provides protection and support.
2.Proteins and carbohydrate chains
Cell Biology
California Biology/Life Science Standard 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?
1.As water molecules enter the cell, the pressure against the cell wall increases. The increase in pressure then slows down the movement of water molecules into the cell.
2.Because a cell membrane is selectively permeable, meaning it allows only some substances to pass through it
Cell Biology
California Biology/Life Science Standard Bl 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.
Question
Name two differences between active transport and diffusion.
Active transport requires energy input from the cell; diffusion does not require energy; diffusion moves materials from an area of greater concentration to an area of less concentration while active transport moves materials against a concentration gradient.
Cell Biology
California Biology/Life Science Standard BI 1.b
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 a reaction by reducing the activation energy needed to get the reaction started. Most enzymes are proteins.
When conditions are too acidic or too alkaline, enzymes do not work as well and reactions are slower than when the pH is optimal.
Questions
1.What happens to the rate of the reaction in the presence of an acid?
2.What happens to the rate of the reaction when a base is added?
1.The reaction is inhibited in the presence of an acid.
2.The rate slows in the presence of a base.
Cell Biology
California Biology/Life Science Standard 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 shapes. 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 a reaction take place?
3.What would happen if a cell lacked a key enzyme?
1. They lower the activation energy needed for the reaction.2. The active site
3. The reaction the cell catalyzes would take place too slowly and the cell might not survive.
Cell Biology
California Biology/Life Science Standard Bl 1 .c
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. Bacteria are prokaryotes.
Eukaryotes contain dozens of specialized structures 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?
1. The microscope 2. Eukaryotic cells contain organelles and are much larger than prokaryotic cells.
Cell Biology
California Biology/Life Science Standard BI 1.c
Quick Review
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.
Questions
1.How do viruses compare to cells in methods
of reproduction?
2.What is one characteristic shared by viruses
and cells?
1.Viruses must enter living cells and exploit host machinery to reproduce; whereas cells reproduce by cell division either asexually or sexually.
2.Sample answer: The fact that they change over time.
Cell Biology
California Biology/Life Science Standard BI 1.d
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 thymine.
Questions
1.Where in the cell does transcription occur?
2.What RNA nucleotide sequence would be
transcribed from the DNA sequence ACG?
1. In the nucleus2. UGC
Cell Biology
California Biology/Life Science Standard BI 1.e
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?
1.Cytoplasm
2.Amino acids
Cell Biology
California Biology/Life Science Standard BI 1.f
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 high-energy 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?
1. The Calvin cycle2. O2, ATP, NADPH3. chloroplasts
Cell Biology
California Biology/Life Science Standard BI 1.g
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?
1.Glucose
2.Krebs cycle and electron transport
Cell Biology
California Biology/Life Science Standard Bl l.h
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?
2.What two forms of carbohydrates are made from long chains of glucose molecules connected in different arrangements?
3.What two important kinds of molecules in all cells are nucleic acids?
1. Carbohydrates—glucose; lipids—glycerol and fatty acids; proteins—amino acids; nucleic acids—nucleotides 2. Starch and cellulose 3. DNA and RNA
Cell Biology
California Biology/Life Science Standard *BI 1.i
Quick Review
Cell membranes contain a protein called ATP synthase 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.
Question
What is the role of ATP synthase during cellular respiration?
To generate ATP
Cell Biology
California Biology/Life Science Standard *BI 1.j
Quick Review
The cytoskeleton helps the cell 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 protein 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?
1.Maintenance of cell shape and support.
2.Paramecia move their cilia like tiny oars to move through liquids