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Bio midterm 1
Ch. 1, 3, 4, 27 vocab
| Term | Definition |
|---|---|
| prokaryotic cells | relatively small, lack internal membrane-bound compartments called organelles |
| eukaryotic cells | much larger, contain many different organelles including central nucleus |
| cell theory | all living things are made of cells, and every new cell comes from the division of a preexisting one |
| organelles | the membrane bound compartments of eukaryotic cells that carry out specific functions |
| cell membrane | all cells are surrounded by this, composed of phospholipids and proteins; flexible yet sturdy structure that forms a boundary between the external environment and the cell's watery interior |
| cytoplasm | watery solution inside every cell, enclosed by the cell membrane |
| ribosomes | structures that synthesize the proteins crucial to cell function |
| DNA | the molecule of heredity that cells contain |
| cell wall | a rigid structure that encloses the cell membrane; what allows bacteria to survive in watery environments (limits how much water can enter into the cell) |
| osmosis | water's tendency to move across membranes |
| hypotonic solution | a solution with a lower solute concentration than that of the cell's own cytoplasm |
| hypertonic solution | solution with higher solute concentration than that of the cell's own cytoplasm |
| isotonic solution | solute concentration is the same as that of the cell's cytoplasm |
| peptidoglycan | polymer made up of sugars and amino acids that link to form a chainlike sheath around the cell; makes the bacterial cell wall rigid; only found in bacteria |
| protists | single-celled eukaryotic organisms |
| contractile vacuole | "water pump" that pumps excess water out of eukaryotic cells with no cell walls |
| gram-positive | bacteria retain the dye (gram stain) |
| gram-negative | bacteria do not retain gram stain |
| streptomycin | first antibiotic that could kill gram neg. bacteria; has a chemical structure that allows it to pass more easily though the outer lipid layer of gram neg. bacterial wall; broad-spectrum antibiotic bc it is effective against both gram neg. and pos |
| phospholipid | 1 component of the cell membrane; has a hydrophilic "head" and a hydrophobic "tail" |
| semipermeable | characteristic of the cell membrane meaning only substances with certain characteristics can cross it easily without help |
| diffusion | natural tendency of dissolved substances to move from an area of higher concentration to one of lower concentration |
| transport proteins | sit in membrane bilayer and are oriented to have one of their ends outside the cell the other inside. They provide passageway for large/hydrophilic molecules to cross membrane; they are also specific (only transport glucose or only calcium) |
| facilitated diffusion | substance moves "downhill" by a transport protein (higher concentration to lower); requires no additional energy like simple diffusion; sometimes known as passive transport |
| active transport | transport proteins pump a substance "uphill"; requires input of energy; keeps antibiotic concentration in cell low |
| nucleus | defining organelle of euk. cells; encloses the cells' DNA and acts as a control center; important reactions for interpreting the genetic instructions contained in DNA take place here |
| nuclear envelope | double membrane made up of two lipid bilayers dotted by small openings called pores that surround the nucleus |
| mitochondria | "power plants": they use oxygen to extract energy from food and convert that energy into a useful form; all eukaryotes have mitochondria and they are essential to life |
| endoplasmic reticulum | vast network of membranes that serves as an assembly line for manufacture of proteins and lipids' can be rough or smooth |
| "rough" ER | studded with ribosomes making proteins |
| "smooth" ER | makes lipids |
| Golgi apparatus | newly made proteins travel here from ER; an organelle that packs the protein "cargo" into small membrane-enclosed sacs called vesicles and then ships them to specific places |
| lysosomes | found in eukaryotic cells; digest and repurpose molecules; thought of as the cell's recycling centers |
| cytoskeleton | vast network of protein fibers; allows cells to move and maintain their shape, much the same way the human skeleton does |
| chloroplasts | found in plant cells, carry out photosynthesis; they also have a cell wall made of cellulose |
| endosymbiosis | the scientific theory that free-living prokaryotic cells engulfed other free-living prokaryotic cells billions of years ago, forming eukaryotic organelles such as mitochondria and chloroplasts |
| malnutrition | a medical condition resulting from a lack of essential nutrients in the diet. often, but not always associated with starvation |
| malnutrition | a medical condition resulting from a lack of essential nutrients in the diet. often, but not always associated with starvation |
| nutrients | the chemical components in the diet that our bodies need to live, grow, and repair themselves |
| nutrients | the chemical components in the diet that our bodies need to live, grow, and repair themselves |
| macronutrients | nutrients that the body requires in large amounts; include carbohydrates, proteins, and fats (a type of lipid) |
| glycogen | energy-storing carbohydrate |
| nucleic acids | a type of macromolecules that make up cells; also broken down into smaller subunits called nucleotides |
| nucleotides | smaller subunits of nucleic acids; cells use them to build DNA and RNA |
| essential nutrients | nutrients that can't be manufactured by our bodies and must be obtained in a pre-assembled form from our diet |
| essential amino acids | 9 amino acids our body can't manufacture and must be obtained pre-assembled from our diet |
| RUTF | ready-to-use therapeutic food; a complete source of nutrition |
| chemical reaction | a process that transforms one set of chemical substances into another by forming or breaking bonds between atoms |
| catabolic reactions | reactions that break down larger structures into smaller ones |
| anabolic reactions | reactions that build new structures from smaller subunits |
| metabolism | all the chemical reactions occurring in the body |
| enzymes | a protein that speeds up the rate of a chemical reaction; work by speeding up, or catalyzing, chemical reactions - a process called catalysis |
| catalysis | the process of speeding up the rate of a chemical reaction (e.g. by an enzyme) |
| substrates | the molecules that enzymes bind to |
| active site | the part of the enzyme that binds to a substrate |
| activation energy | the energy required for a chemical reaction to proceed. Enzymes accelerate reactions by reducing their activation energy |
| potassium | a chemical element required for proper muscle contraction and nerve function |
| minerals | our bodies need these chemical elements to stay healthy; more are required only in small amounts, so they are known as micronutrients |
| micronutrients | small amount of minerals |
| vitamins | organic molecules; another kind of micronutrient |
| cofactors | accessory or "helper" substances that enable enzymes to function; include inorganic molecules like zinc, copper, and iron; can also be organic molecules called coenzymes (most vitamins are important coenzymes |
| astrocytoma | rare brain cancer |
| schwannoma | a type of nerve cell cancer |
| glioma | type of brain tumor |
| anecdotal evidence | based on personal, first hand observations; often unreliable bc only a few data points are involved, ideas are inspired by evidence but not systematically tested |
| scientific evidence | derived from systematic observation and experimentation, hypotheses that are testable and falsifiable are examined, hundreds to thousands of data points are considered |
| peer review | process in which experts int he same field as the investigator review an article before it is published; purpose is to weed out sloppy research as well as overstated claims |
| hypothesis | a possible answer to the question under investigation; must be testable and falsifiable; can never be proven correct with absolute certainty bc no one can test it in every possible scenario |
| control group | does not receive treatment |
| experimental group | receives treatment |
| controlled experiment | an experiment that includes both a control group and experimental group |
| independent variable | factor being changed in a deliberate way |
| dependent variable | the outcome that may "depend" on the independent variable |
| statistical significance | a measure of confidence that the results obtained are "real" and not due to chance; a result has statistical significance when it is unlikely to have occurred by chance alone |
| scientific theory | important hypothesis supported by thousands of scientific experiments; an explanation of the natural world that is supported by a large body of evidence and had never been disproved |
| epidemiology | the study of patterns of a disease in populations, including risk factors |
| case-control study | a type of epidemiology study to assess an association between an exposure and an outcome; type of observational study, the researcher does not manipulate the variable |
| recall bias | a type of error resulting from inaccurate recollection or reporting of past events |
| scientific hypothesis | a testable and falsifiable explanation for a scientific observation or question; not all explanations are scientific hypotheses; can never be proved once and for all; science never provides certainty, proof, or truth |
| p-values | range from 0-1 but are never 1; p<.05 = results are excepted as statistically significant; lower p value = less likely result is due to chance |
| scientific theory | unfalsified hypothesis tested over many years |
| prospective study | looks forward in time to watch for outcomes, such as the development of a disease or not, during the study period and relates this outcome to other factors such as suspected risk or protection factors |
| retrospective study | looking backward in time and examining exposures to suspected risk or protection factors in relation to an outcome that is established at the beginning of the study |
| obesity | medical condition defined as weighing 20% or more than is recommended for one's height or having a BMI or 30 or higher |
| severe (or morbid) obesity | being 200 lbs or more overweight or having BMI or 40 or higher |
| digestion | breaking down of food molecules |
| digestive system | the organ system that breaks down food molecules into smaller subunits, absorbs nutrients, and eliminates waste; consists of the digestive tract and accessory organs |
| digestive tract | essentially a long tube lines with muscles that extends from the mouth to the anus |
| salivary glands | glands that secrete enzymes into the mouth to break down macromolecules in food; one such enzyme is salivary amylase, which digests carbohydrates |
| peristalsis | coordinated muscular contractions that force food down the digestive tract |
| chyme | the acidic "soup" of partially digested food that leaves the stomach and enters the small intestine |
| duodenum | the first part of the small intestine where the various enzymes and pancreatic juices mix |
| bile salts | divide large hydrophobic fat globules into smaller droplets - emulsify them |
| lipase | enzyme secreted by pancreas, chemically breaks down emulsified fats to release their constituent fatty acids and glycerol |
| villi | lining of the small intestine that is folded into fingerlike projections that greatly increase the surface area through which the intestine can absorb nutrients |
| gastric sleeve | type of bariatric surgery; reduced stomach feeds into duodenum; no other changes to digestive tract or digestion |
| gastric bypass | small intestine is cut and surgically attached to reduced stomach; food from stomach is redirected to lower portion of small intestine, bypassing part of stomach and duodenum |
| satiety | the feeling of fullness |
| ghrelin | "hunger hormone"; cells in stomach lining produce this hormone to let the body know its time to eat; these levels fall when the stomach is full (this is a short term regulation) |
| leptin | hormone produced by adipose (fat) tissue; keeps appetite low by inhibiting feeing hormones and stimulate release of anti-eating hormones (this is long term regulation); people who can't produce it overeat to extreme extent |
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