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MCAT Bio. Ch. 1
Term | Definition |
---|---|
Cell Theory's 4 Basic Tenets | All living things are composed of cells. The cell is the basic functional unit of life. Cells arise only from preexisting cells. Cells carry genetic info. in the form of DNA which is passed on from parent to daughter cell. |
Viruses Are Not Considered Living Things Because: | They are acellular, cannot reproduce without the assistance of a host cell, and may contain RNA as their genetic material. |
Eukaryotes Have: | Membrane-bound organelles, a nucleus, and may form multicellular organisms. |
Cell Membrane And Membranes Of Organelles Contain: | Phospholipids, which organize to form hydrophilic interior and exterior surfaces with a hydrophobic core. |
Cytosol Suspends: | The organelles and allows diffusion of molecules throughout the cell. |
Nucleus Contains DNA Organized Into: | Chromosomes. It is surrounded by the nuclear membrane or envelope, a double membrane that contains nuclear pores for two-way exchange of materials between the nucleus and cytosol. |
DNA Is Organized Into Coding Regions Called: | Genes |
Nucleolus | A subsection of the nucleus in which ribosomal RNA (rRNA) is synthesized. |
Mitochondria Contain: | An outer and inner membrane. |
The Outer Mitochondrial Membrane Forms: | A barrier with the cytosol. |
The Inner Mitochondrial Membrane Is: | Folded into cristae and contains enzymes for the electron transport chain. |
Between The Mitochondrial Membranes Is: | The intermembrane space |
Inside The Inner Mitochondrial Membrane Is: | The mitochondrial matrix |
Mitochondria Can Divide Independently Of The Nucleus Via: | Binary fission. This can trigger apoptosis by releasing mitochondrial enzymes into the cytoplasm. |
Lysosomes Contain: | Hydrolytic enzymes that can break down substances ingested by endocytosis and cellular waste products. When lysosomes are released, autolysis of the cell can occur. |
Endoplasmic Reticulum (ER) | A series of interconnected membranes and is continuous with the nuclear envelope. |
Rough ER (RER) Is: | Studded with ribosomes, which permit translation of proteins destined for secretion. |
Smooth ER (SER) Is: | Used for lipid synthesis and detoxification. |
Golgi Apparatus: | Consists of stacked membrane-bound sacs in which cellular products can be modified, packaged, and directed to specific cellular locations |
Peroxisomes Contain: | Hydrogen peroxide and can break down very long chain fatty acids via Beta-oxidation. They also participate in phospholipid synthesis and the pentose phosphate pathway. |
Cytoskeleton Provides: | Stability and rigidity to the overall structure of the cell, while also providing transport pathways for molecules within the cell. |
Microfilaments Are Composed Of: | Actin. They provide structural protection from the cell and can cause muscle contraction through interactions with myosin. They also help form the cleavage furrow during cytokinesis in mitosis. |
Microtubules Are Composed Of: | Tubulin. They create pathways for motor proteins like kinesin and dynein to carry vesicles. |
Microtubules Also Contribute To: | The structure of cilia and flagella, where they are organized into nine pairs of microtubules in a ring with two microtubules at the center (9+2 structure). |
Centrioles Are Found In: | Centrosomes and are involved in microtubule organization in the mitotic spindle. |
Intermediate Filaments Are Involved In: | Cell-cell adhesion or maintenance of the integrity of the cytoskeleton. They help anchor organelles. Common ex's: keratin and desmin. |
Epithelial Tissues Cover: | The body and line its cavities, protecting against pathogen invasion and desiccation. |
Epithelial Cells Form The: | Parenchyma or the functional parts of the organ. |
Simple Epithelia Have: | One layer |
Stratified Epithelia Have: | Many layers |
Pseudostratified Epithelia Appear To Have: | Multiple layers because of differences in cell heights but they actually have only one layer. |
Shapes Of Epithelial Cells: | Cuboidal cells are cube shaped, columnar cells are long and narrow, and squamous cells are flat and scalelike. |
Connective Tissues Support: | The body and provide a framework for epithelial cells |
Connective Tissues Form The: | Stroma or support structure by secreting materials to form an extracellular matrix |
Prokaryotes Do Not Contain: | Membrane bound organelles. They organize their genetic material in a single circular molecule of DNA concentrated in the nucleoid region. |
Archae | Extremophiles that live in harsh environments, have similarities to Eukaryotes (start translation with methionine, similar RNA polymerases, histones) and bacteria (single circular chromosome, divide by binar fission or budding) |
Eukarya | The only non-prokaryotic domain |
Cocci | Spherical bacteria |
Bacilli | Rod-shaped bacteria |
Spirilli | Spiral-shaped bacteria |
Obligate Aerobes | Require oxygen for metabolism |
Obligate Anaerobes | Cannot survive in oxygen-containing environments and can only carry out anaerobic metabolism |
Facultative Anaerobes | Can survive in environments with or without oxygen and will toggle metabolic processes based on the environment |
Aerotolerant Anaerobes | Cannot use oxygen for metabolism, but can survive in an oxygen-containing environment |
Color Of Gram-Positive Bacteria: | Purple |
Color Of Gram-Negative Bacteria: | Pink red |
Thick Cell Wall Of Gram-Positive Bacteria Is Composed Of: | Peptidoglycan and lipoteichoic acid |
Thin Cell Wall Of Gram-Negative Bacteria Is Composed Of: | Phospholipids and lipopolysaccharides |
Chemotaxis | Moving in response to chemical stimuli |
Prokaryotes Multiply Through: | Binary fission in which chromosome replicates while the cell grows in size, until the cell wall begins to grow inward along the midline of the cell and divides it into two identical daughter cells. |
Extrachromosomal Material Of Prokaryotic Cells Are Stored In: | Plasmids which may contain antibiotic resistance genes or virulence factors. |
Episomes | Plasmids that can integrate into the genome |
Transformation | Acquisition of genetic material from the environment, which can be integrated into the bacterial genome |
Conjugation | Transfer of genetic material from one bacterium to another across a conjugation bridge. This allows a plasmid to be transferred from F+ cells to F- cells or a portion of the genome that can be transferred from an Hfr cell to a recipient. |
Transduction | Transfer of genetic material from one bacterium to another using a bacteriophage as a vector. |
Transposons | Genetic elements that can insert into or remove themselves from the genome. |
Lag Phase | Bacterial growth phase in which bacteria adapt to new local conditions |
Exponential Log Phase | Bacterial growth phase in which growth increases exponentially |
Stationary Phase | Bacterial growth phase in which growth levels off as resources as reduced |
Death Phases | Bacterial growth phase in which they die as resources become insufficient |
Capsid | A virus's protein coat that contains genetic material |
Bacteriophages | Viruses that target bacteria, contain a tail sheath which injects the genetic material into a bacterium, and tail fibers, which allow the bacteriophage to attach to the host cell. |
Viral Genomes Can Be Composed Of: | DNA or RNA, and may be single or double stranded |
Single-stranded RNA Viruses May Be Positive Sense, Meaning: | They can be translated by the host cell |
Single-stranded RNA Viruses may Be Negative Sense, Meaning: | A complementary stranded must be synthesized using RNA replicase which can then be translated |
Reverse Transcriptase | Creates a complementary DNA strand for a retrovirus's single-stranded RNA genome |
Extrusion | Process of releasing viral progeny |
Lytic Cycle Of Bacteriophages | Cycle in which the bacteriophage produces massive numbers of new virions until the cell lyses. Bacteria in the lytic pahse are termed virulent. |
Lysogenic Cycle Of Bacteriophages | Cycle in which the virus integrates into the host genome as a provirus or prophage, which can then reproduce along with the cell. |
Prions | Infectious proteins that trigger misfolding of other proteins usually converting an alpha-helical structure to a beta-pleated sheet. This decreases the solubility and degradability of the misfolded protein. |
Viroids | Plant pathogens that are small circles of complementary RNA that can turn off genes, resulting in metabolic and structural derangements of the cell and cell death. |
Created by:
SamB91
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