Cellular and Molecular Biology

5. Endoplasmic Reticulum

A large organization of folded membranes, is responsible for the delivery of lids and proteins to certain areas with the cytoplasm (sort of a cellular highway).

Gene

A length of DNA that encodes a particular protein. Each protein the cell synthesizes performs a specific function in the cell. The function of a protein or a group of proteins is called a trait.

Organism

A living thing

Inorganic Cofactors

A metal ion or other inorganic molecule that is a cofactor in a enzymatic reaction.

Mutation

A mistake in the DNA replication process. These mutations can occur from damage cause to the DNA from chemicals. Most mistakes are fixed, some, however, are not and the cell structure and function can be changed.

5b. Smooth Endoplasmic Reticulum or SER

A network of membranous channels. SEE does not have attached ribosomes. The ER is responsible for processing lipids, fats and steroids, which are then packaged and dispersed by the Golgi apparatus.

7. Smooth Endoplasmic Reticulum

A network of membranous channels. SEE does not have attached ribosomes. The ER is responsible for processing lipids, fats and steroids, which are then packaged and dispersed by the Golgi apparatus.

Cofactor

A non-protein substance required in some enzymatic reactions. The cofactor binds to the active site. This allows the substrate to fit into the active site.

10a. Nucleolus

A rounded area within the nucleus of the cell whee ribosomal RNA is synthesized. This 4RNA is incorporated into ribosomes after exiting the nucleus. Several nucleoli can exists within a nucleus.

6.

A rounded area within the nucleus of the cell whee ribosomal RNA is synthesized. This 4RNA is incorporated into ribosomes after exiting the nucleus. Several nucleoli can exists within a nucleus.

Inhibitor

A substance that attaches to an enzyme's active site that prevents the cellular reaction from taking place. Other factors such as temperature or acidity can also inhibit enzymatic reactions.

Cell Membrane

All cells are enclosed within the cell membrane (or plasma membrane).

Cell Theory

All living things are made up of one or more cells. Cells are the the basic units of life. All cells come form pre-existing cells.

Cellular Metabolism

All types of energy transformation processes, including photosynthesis, respiration, growth, movement, etc. Energy transformations occur as chemicals are broken apart or synthesized within the cell.

1. Golgi Apparatus

Also known as Golgi bodies, or Golgi complex. Instrumental i the storing packaging, and shipping of proteins. Within these membranes, cellular products are stored, or packaged by closing off a bubble of membrane within the proteins or lipids inside. These packages are shipped via the ER to the part of the cell where they will be used, or to the cell membrane for secretion from the cell.

6. Golgi Apparatus

Also known as Golgi bodies, or Golgi complex. Instrumental i the storing packaging, and shipping of proteins. Within these membranes, cellular products are stored, or packaged by closing off a bubble of membrane within the proteins or lipids inside. These packages are shipped via the ER to the part of the cell where they will be used, or to the cell membrane for secretion from the cell.

10. Nucleus

An organelle surrounded by two lipid bilayer membranes. The nucleus contains chromosomes, nuclear pores, nucleoplasm and nucleoli.

5. Nucleus

An organelle surrounded by two lipid bilayer membranes. The nucleus contains chromosomes, nuclear pores, nucleoplasm and nucleoli.

Osmosis

Another type of passive transport. It is a special type of diffusion that only occurs with water molecules. Occurs when the water concentration inside the cell differs from the concentration outside the cell. When water concentration is equal inside and outside the cell, it is isometric or isotonic.

4b. Attached ribosomes

Attached to the ER. Proteins made at the site of attached ribosomes are destined for use within the membrane-bound organelles.

Transformation

Bacteria absorbs and incorporates pieces of DNA from their environment (usually from dead bacterial cells).

Aerobic Respiration

Begins with glycolysis and processed through two major steps, the Krebs cycle and the electron transport,

Cytoplasm

Between the nucleus and the cell membrane. Organelles outside the nucleus, but within the cell membrane are in this cytoplasm, and thus, are called cytoplasmic organelles.

Organelles

Cell components that perform particular functions.

Prophase 1 (1,2)

Chromosome replication occurs before prophase. Then homologous chromosomes pair up and join at a point called a synapse. Crossing over can occur at this point, resulting in an even wider array of final genetic possibilities.

Regulatory Genes

Code proteins that determine functional or physiological events, such as growth. These proteins regulate when other genres stop or start encoding proteins, which in turn produce specific traits.

Structural Genes

Code proteins that form organs and structural characteristics.

Virus structure

Consists of only a protein capsule DMA or RNA, and sometimes enzymes.

Exothermic Reactions

Coupled to the production of ATP or another molecule with high-energy chemical bonds.

Alleles

Different forms of corresponding genes.

Anaerobic

Do not require oxygen for cellular respiration

Facilitated Diffusion

Does not require added energy, but it cannot occur without the help of specialized proteins. These proteins, which are embedded the cell membrane, are able to pick up specific molecules or ions and transport them through the membrane. The special protein molecules allow the diffusion of molecules and ions that cannot otherwise pass through the lipid bilayer.

3b. Microfilaments

Double-stranded chains of proteins which serve to give structure to the cell.

1a. The Cell Membrane

Encloses the cell and separates it from the environment. It may also be called the plasma membrane. This membrane is composed of a double layer (bilayer) of phospholipids with globular proteins embedded within the membrane. The combination of the lipid bilayer and the proteins embedded within it allow the cell to determine what molecules and ions can enter and leave the cell, and regulate the rate at which they enter and leave.

Nomenclature for Enzymes

Enzymes are named ending with the letters -ase, usually begin with a syllable describing the catalyzed reaction (eg. hydrolase catalyze hydrolysis reactions). Thousands of reactions occur within the cells, each controlled by one or more enzymes. Enzymes are synthesized within the cell at the ribosomes, as all proteins are.

Eukaryotic

Eukaryotic cells contain membrane-bound intracellular organelles, including a nucleus. DNA within eukaryotic is organized into two chromosomes. They include plant, fungi and animal cells.

Robert Hooke

First to use the term "cell" when he observed cell walls under a light microscope.

4a. Free Ribosomes

Float unattached within the cytoplasm. The proteins synthesized by free ribosomes are made for use in the cytoplasm, not within membrane-bound organelles.

Substrate

For each enzyme there is a particular substance that fits within the active site.

10. Chloroplasts

Found in plant cells. Chloroplasts are the site of photosynthesis within plant cells. Cloropasts contain green (chlorophyll) yellow and red pigmentation. Depending on the season, different pigmentation is expressed (i.e., green in the summer and spring, yellow and red in the fall). Grana are the site of photosynthetic reactions within the Chloroplasts body (i.e., storm).

9. Cell Membrane

Functions in plant and animal cells the same way. However, in some tissues, channels connect the cytoplasm of adjacent cells.

3. Rough Endoplasmic Reticulum

Has attached ribosomes. Ina addition to packaging and transport of materials within the cell, the RER is instrumental to protein synthesis.

5a. Rough endoplasmic reticulum or RER

Has attached ribosomes. Ina addition to packaging and transport of materials within the cell, the RER is instrumental to protein synthesis.

Prokaryotes

Have no nucleus or any other membrane-bound organelles. The DNA in prokaryotic cells usually form a singe chromosome, which floats in cytoplasm. Prokaryotic organisms have only one cell and include all bacteria.

Anaerobic respiration or Fermentation

If no oxygen is present within the cell, this step occurs after glycolysis. It is not as efficient as aerobic respiration, but ATP is created.

DNA Replication

In order to replicate, a portion of a DNA molecule unwinds with assistance from an enzyme, separating the two halves of the double helix. Another enzyme then assists in the creating of another DNA strand for the two separated strands. If no mistakes are made, the new stands are identical to the parent strands, and the double helix is re-created.

Heme

Included in cytochromes along with proteins.

Photosynthesis

Includes a crucial set of reactions. These reactions convert the light energy from the sun into chemical energy usable by living things. The process can be summed up by: 6CO2 +Light Energy = C6H12O6+6O2 Chlorophyll is not used in this process, but must be present.

Light Microscope

Invented in the mid 1600s that allowed scientist to observe and describe cells.

ATP (Adenosine Triphosphate)

Is known as the energy currency of cellular activity. ATP is an efficient storage molecule for the energy needed for cellular process. When energy is needed it can be broken down into ADP, or AMP (releases more energy). The energy released from these reactions is coupled with energy-absorbing reactions.

Nucleosomes

Long chains of subunits that make up chromosomes. Each nucleosome is composed of a short length of DNA wrapped around a core of small proteins called histones.

3a. Microtubules

Long, hollow, cylindrical protein filaments, which give structure to the cell. These Filaments are scattered around the edges of a cell and form a sort of loose skeleton or framework for the cytoplasm. They are also found at the bas of the cha or flagella and give these organelles the ability to move.

Multicellular Organism

May have many different types of cells that differ in structure to serve different functions. Individual cells may contain organelles that assist them with specialized functions.

Reduction

Meiosis 1. Affects the ploidy level, reducing it from 2n to n.

Division

Meiosis 2. Distributes the remaining set of chromosomes in a mitosis-like process.

8. Lysosomes

Membrane-bound organelles containing digestive enzymes. Lysosomes digest unused material within the cell, damaged organelles, or materials absorbed by the cell for use.

G1 phase

Metabolism and protein synthesis are occurring at a high rate, most of the growth of the cell occurs at this time. The cell organelles are produced and undergo growth during this phase.

Viruses

Much smaller than even the smallest cells. Although they cannot conduct metabolic function on their own, so it is disputed whether they are actually alive. Viruses survive ad replicate by invading a living cell. The virus then utilizes the cell's mechanisms to reproduce itself, sometimes by destroying the cell in the process.

Nucleus

Near the centre of each eukaryotic cell. Contains the chromosomes.

Antonio van Leeuwenhoek

Observed tiny organisms using a light microscope.

Electron Transport

Occurs along the electron transport system, or ETS. This causers the energy in the form of electrons released by the first step. ETS is a series of cytochromes that carry elections and store them in ATP molecules.

Telophase (5)

Occurs as nuclear membranes form around the chromosomes. These chromosomes disperse through the new nucleoplasm.

Cellular Respiration

Occurs in all cells. It is the process that releases energy for use by the cell.

Krebs cycle

Occurs in the matrix of a cell's mitochondria and breaks down pyretic acid molecules into CO2 molecules, H+, and 2 ATP molecules. The Krebs cycle also liberates electrons.

Anaphase 1 (4)

Occurs next as the chromosomes move to separate ends of the cell. This phase differs from the anaphase of mitosis where one of each chromes pair separates.

Metaphase 2 (7), Anaphase 2 (8), Telophase 2 (9) Cytokinesis (10)

Occurs the same as in Mitosis.

Translation

Once Post-Transcriptional Processing is complete, transfer RNA or tRNA is needed. It is the link between the "language" of nucleotides and the "language" of amino acids. Translation occurs at the ribosomes.

Diffusion

One type of passive transport. It is the process whereby molecules and ions flow through the cell membrane from an era of higher concentration to an area of lower concentration.

Organic Cofactors, or Coenzymes

Organic molecules needed in an enzymatic reaction. Some coenzymes are not made by cells, but must be obtained in the diet. Most vitamins are coenzymes.

Homologs

Pairs of chromosomes that come together based on shape and size. Each set of homologous chromosomes has a similar genetic constitution, but genes are not necessarily identical.

Photosynthetic Organisms

Plants, some protists, and some bacteria that are able to to harvest solar energy and transform it into chemical energy eventually stored within covalent bonds of molecules (such as carbohydrates, fats, and proteins).

7. Secretory Vesicles

Pockets of material packaged by either the Golgi apparatus or ER. Secretory vesicles carry substances produced within the cell (a protein, for example) to the cell membrane. The vesicle membrane fuses within the cell membrane in a process called exocytosis, allowing the substance to escape the cell.

10c. Nuclear Pores

Points at which the double nuclear membrane fuses together, forming a passageway between the inside of the nucleus and the cytoplasm outside the nucleus. Nuclear pores allow the cell to selectively move molecules in and out of the nucleus. There are many pores scattered about the surface of the nuclear membrane.

2. Microvilli

Projections of the cell extending from the cell membrane. Microvilli are found in certain types of cells, for example those involved in absorption. These filaments increase the surface area of the cell membrane, increasing the area available to absorb nutrients. They also contain enzymes involved in digesting certain types of nutrients.

Enzymes

Protein molecules that act as catalysts for organic reactions. Enzymes do not make reactions occur that would not otherwise occur under the right energy conditions, but they lower the activation energy, increasing the rate of the reaction.

3 (not listed on diagram) Cytoskeleton

Provides structural support to a cell.

Transcription

Refers to the formation of an RNA molecule, which corresponds to a gene. The DNA strand "unzips" and replicates. The new RNA stand is the messenger RNA, or mRNA. It migrates from the nucleus to the cytoplasm.

2. Mitocondria

Renters of cellular respiration (the process of breaking up covalent bonds within sugar molecules with the intake of oxygen and release of ATP, adenosine try-phosphate). ATP molecules store energy that is later used in cell processes. Mitochondria are more numerous in cells requiring more energy, (like muscle). Mitochondria are self replicating, and have a double membrane with the internal membrane is folded. Cellular respiration occurs along the folds of the internal membrane.

9. Mitochondria

Renters of cellular respiration (the process of breaking up covalent bonds within sugar molecules with the intake of oxygen and release of ATP, adenosine try-phosphate). ATP molecules store energy that is later used in cell processes. Mitochondria are more numerous in cells requiring more energy, (like muscle). Mitochondria are self replicating, and have a double membrane with the internal membrane is folded. Cellular respiration occurs along the folds of the internal membrane.

Aerobic

Require oxygen for cellular respiration

Active transport

Requiring energy output from the cell and membrane-bound proteins. This energy is needed because the molecule is being moved across the cell membrane against a concentration gradient (the opposite direction than they would go under normal diffusion circumstances). The energy used is obtained from ATP.

Prosthetic groups

Smilier to cofactors as they also facilitate the enzyme reaction. But Prosthetic groups are bound to the enzyme, rather than being separate atoms or molecules.

Electron Microscope

Stronger than the light microscope allowing one to observe small cells and more of a cell's organelles.

3c. Centrioles

Structural components of many cells, and are particularly common in animal cells. Their function includes the formation of new microtubules, but is primarily the formation of structural skeleton around which cells split during mitosis and meiosis.

Genomes

Sum total of genetic information

8. Cell Walls

Surround plant cells (bacteria also have cell walls). Cell walls are made of cellulose and lignin, making them wrong and rigid. The cell wall encloses the cell membrane providing strength and protection for the cell. The cell wall allows plant cells to store water under relatively high concentration. The structure of the cell wall allows substances to pass through it readily, so transport in and out of the cell is still regulated by the cell membrane.

Endothermic Reactions

Take place in a cell by being coupled to the breakdown of ATP or a similar molecule.

11. Central Vacuole

Takes up much of the volume of plant cells. It is a membrane-bound fluid-filled space which stores water and soluble nutrients for the plant's use. The Tendency of the central vacuole to absorb water provides for the ridged shape (turgidity) of some plants.

10b. Nuclear membrane

The boundary between the nucleus and the cytoplasm. The nuclear membrane is actually a double membrane, which allows for the entrance and exit of certain molecules through the nuclear pores.

Glycolysis

The breaking down of the six carbon sugar (glucose) into smaller carbon-containing molecules yielding ATP. This is the first step in all respiration pathways ad occurs in the cytoplasm of living cells. It is an anaerobic reaction.

S phase

The cell begins to prepare for cell division by replicating the DNA and proteins necessary to form a new set of chromosomes.

Enzyme control or regulation

The cell may also control enzymatic reactions. This can be done by the product of the reaction is also an inhibitor to the reaction, thus, slowing down the future rate of reactions.

Anaphase (4)

The chromatids are separated from each other when the centromere divides. Each former chromatid is now called a chromosome. The two identical chromosomes move along the spindle fibres to opposite ends of the cell.

Chromatin

The combination of DNA with histones. When a cell is getting ready to divide each strand of chromatin is duplicated.

CO2 fixation

The dark reaction of the photosynthetic process. It occurs in the stroma of the chloroplast. Does not require light, but needs the H and ATP from the photolysis phase. It is in this step the C6H12O6 molecule is formed.

Chromatids

The duplicated chromatins that are attached to each other at the centromere. This chromatid is a duplicated chromosome.

G2 phase

The final phase of interphase. More proteins are produced, which will be necessary for cell division, and the centrioles are replicated as well.

Interphase

The first major period within the cell cycle. It is the period when the cell is active n carrying on its function. Interphase s the period when the cell is active in carrying on its function.

Prophase (1,2)

The first stage of mitosis, the chromatin condenses into chromosomes within the nucleus. The centrioles move to opposite ends of the cell, and spindle fibres begin to extend form the centromeres of each chromosome towards the beginning of the cell.

Endosymbiont hypothesis

The hypothesis that states mitochondria are an evolved form of primitive bacteria (prokaryotic cells) that lived in symbiotic relationship with eukaryotic cells more than 2 billion years ago.

Photolysis

The light reaction of the photosynthetic process. The chlorophyll pigment absorbs a photon of light, leaving the chlorophyll in an excited (higher energy) state. This is a decomposition reaction , separating water molecules into hydrogen and oxygen atoms by using the energy from the excited chlorophyll. The 02 is released into the air from this reaction.

Telophase 1 (5)

The nuclear envelope may o may not form, depending on the type of organism.

Prophase 2 (6)

The nuclear envelopes dissolve and spindle fibres for again.

Mitosis

The process by which a cell distributes its duplicated chromosomes spot that each daughter cell as a full set of chromosomes.

Catabolism

The process of breaking down molecules and releasing stored energy.

Cell Division

The process of cell reproduction

Meiosis

The process of producing four daughter cells, each with single, unduplicated chromosomes, or haploid. The parent cell is a diploid. This occurs in reproductive cells and the result is gametes (sperm or eggs).

Anabolism

The process whereby cells build molecules and store energy in the form of chemical bonds.

Endocytosis

The process whereby large molecules (i.e., some sugars and proteins) are taken up into a pocket of membrane. The pocket pinches off, delivering the molecules, still inside a membrane sack, into the cytoplasm.

Cytokinesis (6)

The producing of two cells.

Exocytosis

The reverse process, exporting substances form the cell.

More on the Cell Membrane:

The selective permeability of the cell membrane serves to manage the concentration of substances within the cell. Substances can cross the cell membrane by passive transport, facilitated diffusion and active transport

Cell Cycle

The sequence of events ending in cell division.

4 (not pictured) Ribosomes

The site of protein synthesis within cells. Ribosomes are composed of certain protein molecules and RNA molecules (ribosomal RNAs, or rRNAs.)

4. Ribosome

The site of protein synthesis within cells. Ribosomes are composed of certain protein molecules and RNA molecules (ribosomal RNAs, or rRNAs.)

The Cell

The smallest and most basic unit of living things

Metaphase (3)

The spindle fibres pull the chromosomes into alignment along the equatorial plane of the cell, creating the metaphase plate. This insures that one copy of each chromosome is distributed to each daughter cell.

Post-Transcriptional Processing

The step occurring once the mRNA has migrated to the cytoplasm. This step prepares the mRNA for protein synthesis by removing the non-coding sequences. In the processed RNA, each unit of three nucleotides or codon encodes a particular amino acid.

Transduction

The transfer of genetic material of a bacterial chromosome from one bacterial cell to another. The transfer is mediated by a bacteriophage (a virus that targets the bacteria.

Metaphase 1 (3)

The two chromosomes align themselves along the equatorial plane of the cell. Each homologous pair off chromosomes contains one chromosome from the mother and one from the father from the original sexual production of that organism.

Active Site

The uniquely shaped area of each enzyme. This unique shape makes enzymes effective as catalysts.

Enzyme-substrate complex

When the substrate is seated in the active site. An enzyme can bind to two substances and catalase the formation of a new chemical bond, linking the two substances. Or it may bind a single substrate and catalyze the breaking of a chemical bond, releasing the two products. Either way the enzyme is unchanged after the reaction has occurred.

1b. Endocytic vesicles

form when the plasma membrane of a cell surrounds a molecule outside the membrane, then releases a membrane-bound sack containing the desired molecule or substance into the cytoplasm. This process allows the cell to absorb larger molecules than would be able to pass through the cell membrane/

Chlorophyll

pigment molecules that give the chloroplast their green colour.

Passive Transport

substances freely pass across the membrane without the cell expending any energy. Eg., Diffusion and Osmosis.