Intro to Cells and Macromolecules Flashcards
What is reductionism?
Knowledge of parts may explain the whole
What are features that define the life we know?
- Reproduction
- Acquiring/using energy
- Metabolism
- Capable of movement
- Respond to stimuli
- Self regulate
What is the central dogma?
Process of transcribing DNA to RNA and translating RNA to proteins.
Who was Robert Hooke and Anton van Leeuwenhoek?
Hooke: first to see cork cells under a microscope and call them cells
Leeuwenhoek: first to see bacteria and describe them as animalcules
Who was Matthias Schleiden and Theodor Schwann?
Schleiden: observed plant tissues were made of cells and that embryos come from a single cell
Schwann: observed animal tissues were made of cells and proposed the first two tenets of the cell theory.
Who was rudolf virchow?
Observed cell division and proposed the third tenet of Cell Theory
What is the Cell Theory?
- All organisms are composed of one or more cells
- A cell is the basic structural unit of life for all organisms
- Cells only arise from preexisting cells
What is the difference between a prokaryote and a eukaryote?
Prokaryotes: single celled organisms with a non-membrane bound nucleus, non-membrane bound organelles, that is 1-10µm
Eukaryotes: single or multicellular organism with a membrane bound nucleus, membrane bound organelles, and is 10-100µm
What are the different types of bacteria shape, oxygen use, nutrition, and special features?
Shape: cocci, bacillus, spirillum
Oxygen use: aerobic, strictly anaerobic
Nutrition: inorganic or organic substances
Features: may have the ability for nitrogen fixation, may be photosynthetic
What is archaea?
Prokaryotic extremophile identified via DNA sequencing that lives in hostile environments.
What are the parts of a cell?
Nucleus: information store of cell enclosed within nuclear envelope
Mitochondria: generate usable energy from food molecules
Chloroplasts: capture energy from the sunlight
Endoplasmic Reticulum: site of protein synthesis
Golgi apparatus: transports, sorts and modifies both proteins and lipids
Cytosol: concentrated aqueous gel that suspends organelles
What are viruses?
Microbes made of bits of nucleic acid surrounded by a protein coat that reproduce only in cells.
What are virioids and prions?
Virioids: circular RNA without protein coat
Prions: proteinaceous infections particles
What are macromolecules?
Huge, highly organized molecules that form the structure and carry out the activities of cells.
What are the 4 major categories of macromolecules and their monomers?
Lipids (fatty acids), carbohydrates (monosacharrides), nucleic acids (nucleotides), and proteins (amino acids)
What is a polypeptide?
Polymer of amino acids linked via peptide bonds
What are general functions of proteins? (ESCGTCHA)
- Enzymes
- Structural elements
- Contractile elements
- Gene transcription
- Transport proteins
- Carriers
- Hormones
- Antibodies
What are amino acids?
ORganic acids that contain an amino group, carboxylic group, alpha carbon and R group that act as the building blocks of proteins
What is an R side chain? What properties does it have?
A side chain of variable structure on an amino acid and influences tertiary structure. Can be nonpolar, polar, acidic, basic, charged and uncharged.
How do polypeptides form?
Dehydration reaction: H of amine in N terminus bonds with OH in carboxylic acid in C terminus to produce a water molecule.
What are the 4 levels of structure in a protein?
Primary: Specific sequence of amino acids (residues) in a polypeptide from N terminus to C terminus
Secondary: hydrogen bonds between carbonyl and amino groups in peptide backbone that form alpha helices or beta sheets
Tertiary: side chain interactions via hydrogen bonds, hydrophobic forces, electrostatic interactions, and disulfide bonds.
Quaternary: spatial arrangement of multiple protein subunits
What is cellulose?
Linear polymer of several hundred to thousand glucose units. It is insoluble and rigid, only broken down by bacteria, and makes up the cell wall of plants.
What are nucleotides made of?
nitrogenous base, pentose sugar, and phosphate group
What 3 major functions are nucleotides involved in?
- Genes: encode and read out genetic information of the cell
- Regulatory molecules: second messengers in signalling (cAMP), activation of proteins (G-Proteins)
- Energy transfer: cleaving releases energy (ATP), co-enzymes in energy transfer reactions (NAD)
What are the nitrogenous bases?
Purine: Adenine, Guanine
Pyrimidine: Cytosine, Thymine, Uracil
What are lipids structure and function?
Strucrture: diverse hydrophobic organic molecules insoluble in H2O but soluble in nonpolar organic liquids
Function: store energy (fats/oils), act as hormones (steroids, prostaglandins), vitamins, membrane structure
How do we see cells through a microscope?
Light is focused on the specimen by lenses in the condenser as the light passes through objective lenses and tube lenses.
What is the limit of resolution?
Smallest distance between two points that can be distinguished as separate entities. In a conventional light microscope, it is not possible to resolve two objects separated by less than 0.2 µm
What is bright field microscopy?
Light is transmitted straight through specimen
What is phase contrast microscopy?
phase alterations of light transmitted through the specimen are translated into brightness changes
What is differential interference contrast microscopy?
Highlights edges where there is a steep change of refractive index
How does fluorescent microscopy work?
Fluorescent molecules absorb light at one wavelength and emit it at another, longer wavelength. This illuminates the molecule at its absorbing
How do we locate particular molecules to bind fluorescent dyes to?
Antibodies are coupled to fluorescent dyes which allows the labeled antibody to bind to a specific target in the cell. This target is detected through a fluorescence microscope.
What is green fluorescent protein?
Molecule that gives jellyfish their greenish glow. When fused to the sequence of a gene of interest, it may be expressed and monitored by fluorescence microscopy.
What is confocal microscopy?
Excites a point at a time and scans the field of view, generating a sharp image of hte plane of focus
What is super-resolution microscopy?
Bleaches surrounding area to improve contrast.
How does the transmission electron microscope work?
Uses beam of electrons (short wavelength) instead of a beam of light, and uses the electrons that have passed through the specimen (dead in a vacuum and coated with metals) to form an image.
What is a scanning electron microscope?
Uses electrons scattered or emitted from the specimen’s surface to produce an image of the 3D structure of the surface of a specimen.
