Results for "subunits"

Cell theory organisms are composed of 1+ cells, which are the smallest unit of life, which come from pre-existing cells What do Prokaryotic Cells have? - Cell wall - Plasma Cell membrane -Flagella -Ribosomes -Nucleoid Cell Wall made of of carb protein complex, PEPTIOGLYCAN, allows for cell to hold shape Plasma Membrane Controls movement of materials in and out of cells, plays role in binary fission Cytoplasm -occupies interior, no compartmentalization, site of all chemical processes in the cell -Region where organelles can be found Capsule some, not all have this, made of polysaccharide, sticky and allows for attachment to surfaces Pili short hair growth on cell wall, used for attachment, joins bacteria cells to prep for DNA transfer Flagella longer than pili, used for movement Ribosomes where protein synthesis occurs, in big numbers in cells that require high protein content Nucleoid Region non-compartmentalization and has a single long thread of DNA, controls cells and reproduction Plasmids small circular DNA molecules, not connected to main loop Binary Fission the simple cell division, process where DNA is copied and the daughter chromosomes become attached to different regions on the membrane, cell elongates and divides into 2 identical daughter cells Microscope DOs -careful -proper carrying -using for intended purpose Microscope Don'ts -squinting -carrying with one hand -using coarse focus knob on high power -leaving at edge of lab bench Characteristics of Prokaryotic Cells -DNA is circular, not enclosed -Free DNA -Non-membrane bound organelles -70s ribosomes -Very small -Division by binary fission SURFACE AREA TO VOLUME RATIO does what? What does this do? Limits cell size, the bigger this ratio, the more efficient it is for the diffusion to take place in and out of the cell. Differentiation process whereby cells develop into specific cells as a result of the expression of certain genes but not others What are stem cells? Cells that retain their ability to divide into various types of cells. What type of tissue in plants contains stem cells? Meristematic tissue. Where are stem cells found in animals? In embryos. Cytosol Fluid portion of cytoplasm What is the endoplasmic reticulum? An extensive network of tubules and channels that extends almost everywhere from the nucleus to the plasma membrane. What is the function of the endoplasmic reticulum? Transports materials throughout the internal region of the cell. Rough ER has ribosomes on its surface and is therefore involved in protein development and transport. Smooth ER lacks ribosomes on its exterior but contains unique enzymes embedded on its surface. 6 functions of the smooth ER 1. production of membrane phospholipids and cellular lipids 2. Production of sex hormones such as testosterone and estrogen 3. Detoxification of drugs in the liver 4. Storage of calcium ions needed for contraction in muscle cells 5. Transportation of lipid-based compounds 6. Aid the liver in releasing glucose into the bloodstream when needed What are ribosomes? Structures that have no exterior membrane What is the primary function of ribosomes? Carry out protein synthesis What are ribosomes composed of? A type of RNA and a protein How many subunits do ribosomes have? Two subunits What are lysosomes? Intracellular digestive organelles that arise from the Golgi apparatus. What do lysosomes catalyze the breakdown of? Proteins, nucleic acids, lipids, and carbohydrates. Golgi apparatus Responsible for the collection, packaging, modification, and distribution of materials synthesized in the cell Two sides : cis and trans cisternae Golgi apparatus is composed of a stack of flattened sacs called this What shape are mitochondria? Rod-shaped What are mitochondria commonly referred to as? The cell's powerhouse Do mitochondria have their own DNA? Yes, it is similar to that of bacterial cells What type of membrane do mitochondria have? Double-membraned How is the outer membrane of mitochondria described? Smooth What are the folds in the inner membrane of mitochondria called? Cristae matrix Inside the mitochondria inner membrane is fluid called this What is the function of the cristae in mitochondria? The cristae provide a huge internal surface area for the chemical reactions in the mitochondria to occur. What type of ribosomes do mitochondria produce and contain? Mitochondria produce and contain their own ribosomes. What is the primary energy molecule produced by mitochondria? ATP (adenosine triphosphate). What is the nucleus? A compartmentalized region where DNA can be found. What is the nuclear envelope? A double membrane that covers the nucleus. What do the pores in the nuclear envelope allow? Communication with the cell's cytoplasm. What are chloroplasts? Organelles that can only be found in algae and plant cells. What type of membrane do chloroplasts have? Double-membraned. What unique genetic material do chloroplasts contain? Their own ribosomes and DNA in the form of a ring. What structures are found in the interior of chloroplasts? Grana, thylakoids, and the stroma. Granum made up of a stack of thylakoids Thylakoids flattened membrane sacs with components essential for the absorption of light Stroma similar to cytosol; contains many enzymes and chemicals essential to complete the process of photosynthesis What is a centrosome? A structure that consists of a pair of centrioles at right angles to one another. What is the function of centrioles in the centrosome? They are involved in assembling the microtubules necessary for providing structure and movement in the cell. Why are microtubules important for cells? They are necessary for cell division. In which types of cells are centrosomes found? Centrosomes are found in animal, fungal, and most protoctist cells, but not in higher plant cells. What are vacuoles? Storage organelles that usually arise from the Golgi apparatus. What substances do vacuoles store? Potential food, metabolic wastes and toxins, and water. How do vacuoles affect cell size? They allow cells to have a higher surface area to volume ratio even at larger sizes. What role do vacuoles play in plant cells? They allow the uptake of water to provide rigidity to the cell.

BIOC 503 - LIPID BIOSYNTHESIS

Systems: macromolecules and subunits

BIOC 503 - ELectron Transport Chain (ETC)

NEUS 609 - Neurotransmitters & their Receptors

History subunits

Ribosomal Subunits

Classification of different subunits

Consensus Sequences associated with Alternate Sigma Subunits of E

Receptor Subunits

smallest subunits in myology to largest

BIOL 1140 Chapters 15-16 Review Worksheet KEY Define transcription Transcription is the process of creating RNA from DNA. Describe how only one strand of DNA is used as the template in transcription. Only one of the strands (3’-5’ strand) serves as a template; the other strand is unused. Identify the three steps of transcription and briefly what is happening in each step. Initiation - in this step, the enzyme *RNA polymerase attaches to a region of the gene called a promoter, and transcription starts Elongation – In elongation, the enzyme RNA polymerase zips along the DNA strand adding complementary nucleotides to the DN template. The newly made RNA is fed out the back of the enzyme, and the two DNA strands re-anneal (re-zip). Remember that adenine, guanine, and cytosine are used in making RNA, but uracil is used in place of thymine. Termination - in this step, RNA polymerase reaches a sequence of nucleotides on the DNA template called a terminator. RNA polymerase then detaches from the newly synthesized RNA and the DNA. *before RNA polymerase binds, a series of proteins called transcription factors first bind to the promoter. Once they bind, they “recruit” RNA polymerase to the promoter. The binding of RNA polymerase starts the transcription process Which of the following statements regarding transcription is not true? A. The three stages of transcription are initiation, elongation and termination B. The key enzyme responsible for transcription is RNA polymerase C. Transcription is the conversion of information from DNA nucleotides into RNA nucleotides D. Transcription in eukaryotes is regulated (in part) by the binding of transcription factors to the promoter E. All are true statements What is the name of the enzyme used in transcription? Where does this enzyme bind? RNA polymerase…it binds to the gene’s promoter (though it doesn’t bind directly to the DNA strand) Indicate if the following statements about codons, amino acids and the genetic code are true or false: ____True______ A codon is a three nucleotide sequence that codes for a specific amino acid ____ True ______ In the genetic code, a codon will code for only one amino acid; that is there is specificity on the genetic code. ____False______ Some codons consist of only two nucleotides. 🡪 all are three nucleotides _____False_____ Some amino acids are not specified by any codons. 🡪 all amino acids have their own set of codons ____ True ______ Some codons (“stop codons”) do not code for any amino acid. ____ True ______ More than one codon can code for the same amino acid; that is, there is redundancy in the genetic code. Define translation. Translation is the process of creating proteins from RNA. Match the key players in translation with their function Answers B_____ tRNA A) The kind of RNA that makes up a ribosome. D______ mRNA B) Acts as the ‘interpreter’ in translation, by bringing in amino acids. C_______ DNA C) The genetic information in a cell. A_______ rRNA D) The kind of RNA that codes for amino acids. E_______ Ribosome E) Where translation takes place. Identify the three steps of translation and briefly describe what is happening in each step. Initiation – First an mRNA molecule binds to the small ribosomal subunit. A special initiator tRNA binds to a specific codon called the start codon (AUG = methionine). The initiator tRNA which carries the amino acid methionine, binds its anticodon (UAC) to the start codon . Second, a large ribosomal subunit binds to the small one, creating a function ribosome. The initiator tRNA binds to one of two tRNA binding sites on the ribosome. Elongation - In elongation amino acids are added one-by-one to the first amino acid. Each addition occurs in a three-step process: 1st: the anticodon of an incoming tRNA molecule, carrying its amino acid, pairs with the mRNA codon. 2nd: the incoming amino acid attaches by peptide bond to the amino acid already present – the formation of the bond is catalyzed by the ribosome. 3rd : The tRNA already present moves over to the next site (the codon and anticodon remain hydrogen bonded and the mRNA and tRNA move over as a unit), allowing another tRNA to move in. The second amino acid is then added to the growing polypeptide chain. The process is repeated - the first tRNA leaves the ribosome, the second tRNA moves over, allowing room for the next to move in…the process is repeated over and over again Termination - Elongation continues until a stop codon reaches the ribosome (recall that a stop codon does not code for any amino acid). The completed polypeptide is freed from the tRNA and the ribosome splits back into two separate subunits. Which of the following statements regarding translation is not true? A. Translation is the conversion of information from nucleic acids to proteins B. Translation takes place in the nucleus C. During translation, amino acids are linked to one another by peptide bonds D. Polypeptides made during translation must still be modified to become fully-functioning mature proteins E. All are true statements

G protein subunits

G-alpha subunits

Micro Exam 4 Virus - a genetic element that contains either RNA or DNA surrounded by a protein capsid and that replicate only inside host cells Obligate intracellular parasite - Cannot multiply unless they invade a specific host cell and instruct its genetic and metabolic machinery to make and release new viruses Capsid - the protein shell that surrounds the genome of a virus Nucleocapsid - nucleic acid + protein in enveloped viruses Envelope - viruses have an outer layer consisting of a phospholipid bilayer (from host cell membrane) and viral proteins – those without envelope are easier to kill Virion – inactive form of virus outside the host cell Capsomere - identical protein subunits that spontaneously self-assemble into a finished capsid icosahedron – one of 2 types of capsids (the other is helical) Genome - the sum total of the genetic information carried by an organism Bacteriophage - “bacteria eating” viruses that infect bacteria Temperate phage: Undergo adsorption and penetration, do not undergo replication or release immediately Viral DNA enters a Prophage state Inserted into bacterial chromosome → Copied during normal bacterial cell division Induction - prophage in a lysogenic cell becomes activated and progresses directly into viral replication and the lytic cycle lysogeny - a condition in which the host chromosome carries bacteriophage DNA lysogenic conversion - when a bacterium acquires a new trait from its temperate phage: Corynebacterium diphtheriae – diphtheria toxin Vibrio cholerae – cholera toxin Clostridium botulinum – botulinum toxin Monolayer - single, confluent sheet of cells that supports viral multiplication Plaques - areas where virus-infected cells have been destroyed show up as clear, well-defined patches in the cell sheet