Cell Structure + Physiology Flashcards
anatomy definition
the science of the structure of the body and its relation of its parts
physiology definition
the science of how the body functions
What is a cell?
the basic unit of life
what are the two kinds of cells?
1) prokaryote
2) eukaryote
Prokaryote
- before nucleus
- a cell thats lacks a true membrane bound nucleus + organelles
- ALL bacteria are prokaryotes
Eukaryote
- is a cell w/ a membrane-bound nucleus + organelles
- ALL multicellular organisms are composed of eukaryotic cells
What is a eukaryote consisted of?
cell membrane, cytoplasm, nucleus
Cell membrane is also known as what
plasma membrane
Characteristics of a cell membrane
- separates the cell from its external environment
- contains a double phospholipid bilayer w/ interspersed proteins (fluid-mosaic model) which also contains carbohydrate chains + cholesterol
- is semipermeable
- have surface modifications
what does it mean for the cell membrane to be semi-permeable?
allows various substances to move in and out of the cell
what are the surface modifications of a cell membrane?
- cilia
- flagellum
- microvilli
What are cilia?
- hairlike projections
- used for movement
What are flagellum?
- a single longer projection
- used for cellular movement
What are microvilli?
- increases surface area (esp. in absorptive cells)
What are the characteristics of the cytoplasm?
- encompasses everything w/in the cell EXCEPT the nucleus
Organelles w/in the cytoplasm are _____ & have _______ .
specialized and have many functions
What organelles are located in the cytoplasm?
ribosomes, mitochondria, endoplasmic reticulum (smooth, rough), golgi complex (golgi apparatus), lysosomes, peroxisomes, cytoskeleton, centrioles
Ribosomes
- freely moving or attached to the ER
- composed of protein and ribosomal RNA
- site of protein synthesis
Mitochondria
- “powerhouse of the cell”
- contains mitochondrial DNA + protein
- Has a double membrane
Inner membrane of the mitochondria
Extends into folds known as cristae
What are cristae?
- folds in the mitochondria
- increases the surface area for production of ATP
How are ATP produced in the mitochondria?
produced through the process of cellular respiration (Krebs cycle, citric acid cycle, tricarboxylic acid cycle)
Cells that use A LOT of energy have A LOT of ______
mitochondria
What are the two kinds of endoplasmic reticulum?
Smooth + Rough
What is the rough ER?
- hollow system of flattened membranous channels w/ attached ribosomes
- acts are a transportation network for proteins
What is the smooth ER?
- hollow system of flattened membranous channels w/o attached ribosomes
- NOT involved in protein synthesis
Function of the smooth ER?
- synthesizes cholesterol, steroid-based hormones, lipids; detoxifies drugs; breaks down glycogen; transports fats
What type of cells have LARGE AMOUNTS of SER?
liver cells, intestinal cells, interstitial cells of the testes
What is the Golgi complex?
- serves as a receiving, packaging, + distribution center
- stacked, saucer-shaped membranes
Function of the golgi complex
- modifies and synthesizes the carbohydrate portion of glycoproteins
- packages substances from the ER and then exports them from the cell or releases them into the cytoplasm for internal use
- produces lysosomes
Lysosomes
- contains digestive enzymes that digest intracellular bacteria and breaks down nonfunctional organelles
- are principle organelles in digestion of nutrients
What do lysosomes perform?
autolysis
What is autolysis? When do lysosomes perform autolysis?
self destruction of the cells; occurs if the enzymes are released into the cytoplasm
What type of cell has LARGE amts of lysosomes?
phagocytic cells
Peroxisomes
- membrane bound organelles that contain strong oxidase + catalase enzymes
- uses O2 to detoxify toxic substances (esp. alcohol + formaldehyde)
- converts free radicals into hydrogen peroxide which is converted to water via catalase enzymes
What are free radicals?
normal by-products of cellular metabolism but harmful if left to accumulate
In what type of cells are LARGE amounts of peroxisomes found?
liver cells + kidney cells
What is the cytoskeleton consist of? What are its functions?
- consists of microtubules, microfilaments, intermediate filaments (all made of proteins)
- provides internal framework that gives the cel it’s form, structure, support
- anchors organelles
- enables movement
What are centrioles? What is its function?
- microtubules arranged to form a hollow tube
- important in organizing the mitotic spindle
- forms the base of cilia + flagella
What is the nucleus? What is its function?
- control center of the cell
- contains DNA (governs heredity + protein synthesis)
- has a double, semipermeable nuclear envelope (membrane)
- contains one or more nucleoli (manufactures the ribosomal units)
What are the two forms of DNA?
chromatin: non-dividing cell
chromosomes: dividing cell
