Cell Organelles Flashcards
What is the cytoplasm?
Consists of:
-cytosol (water, K+, proteins, amino acids, lipids, and carbohydrates)
-organelles
-inclusions (insoluble, ex. glycogen granules, pigments)
How much space does the cytosol take up within the cell?
55% cell volume
What is the cytoskeleton made up of?
Microfilaments (actin), thick filaments (myosin), intermediate filaments (keratin), microtubules (tubulin)
What are cilia?
5-10 um in length, made of microtubules that helps movement and flow
found in the trachea, fallopian tubes
What are flagella?
50 um in length and helps with movement
-only found on sperm cells
What are centrosomes?
Pair of centrioles at right angles, migrate to poles during mitosis
organize and move the spindle fibers in dividing cells, necessary for cell division
Which cells do not have centrioles?
Red blood cells, skeletal muscle cells, cardiac muscle cells, most neurons
What are proteasomes?
Hollow cylinders of proteolytic enzymes (breaks down proteins) with regulatory proteins at their ends
breaks down and recycles damaged and abnormal intracellular proteins
What are ribosomes?
RNA + proteins; fixed ribosomes bound to rough endoplasmic reticulum, free ribosomes scattered in cytoplasm
site of protein synthesis
What are mitochondria?
Double membrane with inner membrane folds (cristae) enclosing important metabolic enzymes
site of cellular respiration, produces 95% of the ATP required by the cell
What are the membranous organelles?
Nucleus, endoplasmic reticulum, mitochondria, golgi apparatus, plastids, lysosomes
What are the non-membranous organelles?
Ribosomes, centrioles, cilia, flagella, microtubules, microfilaments, and intermediate filaments
What is the endoplasmic reticulum and what are the functions?
A network of membranes connected to membranous nuclear envelope
-Synthesis of proteins, carbohydrates, phospholipids, cholesterol, and steroid hormones
-Storage of TGs, glycolipids, Ca2+
-Transport
-Detox-drugs are metabolized; toxins are neutralized by enzymes
What does the smooth endoplasmic reticulum do?
Synthesis of lipids, secretion of hormones, detoxification/metabolization of drugs, and large Ca2+ store, many present in the liver
What does the rough endoplasmic reticulum do?
Protein synthesis, modification and folding, and manufacturing of phospholipids
What does the golgi body do?
A stack of flattened membrane (cisternae) containing chambers that processes and packages proteins, stores, alters and packages secretory produces and lysosomal enzymes
packages the newly synthesized proteins and lipids from the endoplasmic reticulum
-hormones or matrix proteins are exported
-digestive enzymes are packaged into vessels to form lysosomes
What are lysosomes?
Contain digestive enzymes that break things down
intracellular removal of damaged organelles or pathogens
What are secretory vesicles?
Contain hormones and proteins for export, specific to the cell and then exports using exocytosis
What are membrane renewal vesicles?
Vesicles that contain lipids and proteins for membrane repair
What are peroxisomes?
Vesicles containing degradative enzymes
catabolism of fats and other organic compounds; catalase neutralization of toxic compounds (H2O2 hydrogen peroxide) generated in the process
What is autolysis
Cell self-digestion of the cell when it is inactive or damaged
it is not planned for, rather occurs when something is wrong with the cell
occurs in unhealthy cells
What is apoptosis?
Apoptosis is programmed cell death that is planned for worn out cells to be disposed of in an orderly fashion
Occurs in healthy cells
What are the differences between apoptosis and autolysis?
Apoptosis is planned for while autolysis is not
autolysis results with the death of injured or diseased cells, whereas apoptosis is programmed for healthy cells at a certain point
What is the nuclear envelope?
Membrane double layer of lipids that protects the cell’s DNA and regulates entry and exit into the nucleus
What can cross through the nuclear pore?
Small molecules, ions, mRNA (not DNA or proteins, as they are too large to enter)
What is a nucleus?
Largest organelle in the cell
Nucleoplasm containing nucleotides, enzymes, nucleoproteins, and chromatin; surrounded by a double lipid membrane (nuclear envelope)
It functions as the control center of a cell and controls metabolism, storage and information processing of genetic information; control of protein synthesis
-contains nuclear lamina: scaffolding protein network of intermediate filaments that supports shape
-consists of rDNA and protein
-larger in muscle and liver cells as they produce a lot of protein
What is a nucleolus?
Site of rRNA synthesis and assembly of ribosomal subunits
What are nuclear pores?
About 10% of the nuclear envelope and facilitates entry to the nucleus
allows for diffusion of small molecules and ions; active transport of large proteins
In what form can DNA be found in the nucleus?
Chromatin and chromosome
What is chromatin?
Uncoiled DNA which supercoils (condenses) during prophase and decondenses during telophase
What are the 3’ and 5’ ends of DNA?
Corresponding to the carbon numbering of deoxyribose
What direction does DNA polymerase join nucleotides together?
5’ to 3’ direction
What does the DNA helicase do?
Helix enzyme unwinds the strands and disrupt the hydrogen bonds
What does DNA Ligase do?
DNA ligase enzyme joins two DNA segments with covalent bonds
What kind of membranes are present within the Golgi body?
Cisternae; stacks of flattened membranes containing chambers
What kind of membranes are present within mitochondria?
Cristae; inner membrane folds that enclose important metabolic enzymes
Which is the correct sequence of events when the RER delivers transport vesicles to the golgi apparatus?
How are chromosomes formed?
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