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A&P 1 > Cellular Organization (chapter 3) > Flashcards

Cellular Organization (chapter 3) Flashcards

1
Q

Cell

A

smallest living unit

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2
Q

Cytology

A

study of cells, requires microscope

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3
Q

Two categories of cells

A

1.sex cells: sperm and oocyte(egg)
2.somatic cells: everything else

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4
Q

Plasma Membrane/Cell Membrane

A

-mostly phospholipid bilayer: dynami
-6 to 10mm thick
-interface between cell and enviornment

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5
Q

Plasma membrane functions

A

-physical barrier to maintain homeostasis: separates intracellular contents (cytoplasm) from extracellular fluid
-regulates exchange with environment
-provides sensitivity via receptors: cell communication and signaling, sense change in extracellular environment
-provides structural support: attachment site to hold tissues together

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6
Q

Plasma membrane components

A

A. phospholipids: self assemble into bilayer
B. cholesterol: resist osmotic lysis: stiffens
C. carbohydrates: linked to other molecules as proteoglycans, glycoproteins, and glycolipids
-carb part protrudes from extracellular side creating outer carb layer called glycocalyx
D. proteins:
-1/2 mass of membrane
-integral proteins: (most common) span width of membrane
-peripheral proteins adhere to inner or outer surface

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7
Q

Functions of glycocalyx

A

-lubrication and protection
-anchoring and locomotion
-binding specificity (receptor binds ligands)
-self recognition by immune system

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8
Q

Functions of membrane proteins

A

-anchoring proteins: attachment (both inside and outside)
-recognition proteins: self identification by immune system (glycoproteins)
-enzymes: catalyze rxns in cytosol or extra cellular fluid
-receptors: bind ligands for signaling or import/export (e.g ions, nutrient molecules, hormones, etc)
-carrier proteins: transport solutes in/out
-channels: move ions and H2O in/out

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9
Q

Facilitated diffusion

A

movement of materials across a membrane by a carrier protein
-substances involved simple sugars and amino acids

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10
Q

Osmosis

A

diffusion of water molecules across a selectively permeable membrane. Movement occurs toward higher solute concentration because that is where the concentration of water is lower.
-substances involved water only

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11
Q

Diffusion

A

is the movement of molecules from an area of higher concentration to an area of lower concentration.
-substances involved gasses, small inorganic ions and molecules, lipid soluble materials

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12
Q

Transcription

A

-making an RNA copy of a DNA gene
-occurs in the nucleus

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13
Q

Translation

A

making a protein using the mRNA blueprint
-occurs in the cytoplasm on free ribosomes or on fixed ribosomes on the RER

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14
Q

Active Transport

A

requires proteins that move specific substances across a membrane against their concentration

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15
Q

Endocytosis

A

packaging of extracellular materials into a vesicle for transport into the cell

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16
Q

Exocytosis

A

intracellular vesicles fuse with the plasma membrane to release fluids and or solids from the cells

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17
Q

Cytoskeleton

A

-internal framework
-organizes cell contents and functions
-4 possible types of filaments:
A. Microfilaments
B. Intermediate filaments
C. Microtubules
D. Thick filaments

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18
Q

Centrosome

A

-located near nucleus
-consists of dense cytoplasm and two centrioles arranged at right angels
-functions as microtubule organizing center
-responsible for assembling spindle apparatus during mitosis

19
Q

Cilia

A

-cellular appendages
-contain a microtubule core with cytoplasm covered in plasma membrane
-beating or waving motions
-short, numerous, functio to sweep substances over cell surface

20
Q

Flagellum

A

-Very long, singular function to propel cell through environment

21
Q

Ribosomes

A

-site of protein synthesis: enzymes to peptide bond amino acids
-2 subunits: large and small both composed of 60% rNA and 40% protein
A. Free ribosomes: in cytoplasm, manufacture proteins for use in cytoplasm
B. Fixed ribosomes: attached to ER, manufacture proteins for export or for in the membrane

22
Q

Endoplasmic Reticulum

A

-network of membranes made up of tubes sacs and chambers called cisternae
-attached to the nuclear envelope
-2 forms: RER and SER

23
Q

Rough ER

A

-studded with fixed ribosomes
-ribosomes synthesize proteins and feed them into RER cisternae to be modified
-modified proteins put into transport vesicles to go to golgi
-these proteins for exocytosis or use in membrane

24
Q

Smooth ER

A

-tubular membranes
-no ribosomes
functions of SER
1. synthesis of phospholipids and cholesterol for membrane
2. synthesis of steroid hormones
3 synthesis and storage of triglycerides
4. synthesis and storage of glycogen
5. storage of Ca2+ ions in muscle cells
6. detoxification/inactivation of drugs in kidney and liver cells

25
Q

Golgi

A

-stack of cisternae with an associated transport vesicles
-near nucleus but not attached
-functions:
A.modifies and packages secreations
B. renews or modifies the cell membrane
C. packages enzymes within vesicles to create a temporary digestive organelle called the lysosome
-transport vesicles from RER dock on cisternae face or forming face of golgi
-proteins (and glycoproteins) are modified (phosphate, carbohydrates, or lipids attached, polypeptides, refolded)
-modified proteins transit between cisternae via vesicles from cis face (forming) to trans face (maturing) and are concentrated and sorted by final function and destination
-at trans face proteins are packaged into one of three types of vesicles for transport

26
Q

Three types of Vesicles for transport

A

A. secretory vesicles: carry products to be exocytosed for use outside the cell
B. membrane renewal vesicles: carry products to be incorporated into the plasma membrane
C. lysosomes: temporary organelles membrane bound sacs of digestive enzymes

27
Q

Lysosomes

A

-digestion center for large molecules or structures, cell can have many
-functions:
A. cellular cleanup: remove and recycle damaged organelles and extra molecules
B. break down material and objects that have been endocytosed
-endosomes or phagosomes containing endocytosed things and organelles and molecules targeted for destruction are fused with the lysosome and enzymatically broken down
-some solutes diifuse into cytoplasm for use remaining debris are exocytosed
-failure of lysosomes causes build up of cells that eventually prevents cell functions e.g Tay Sach’s disease

28
Q

Peroxisomes

A

-membrane sac containing oxidases and catalases to neutralize free radicals
-free radicals (e.g H2O) form during catabolism of organic molecules
-peroxisomes not made by golgi enzymes produced by free ribosomes, cell can have many

29
Q

Proteasomes

A

-cylindrical structure composed of protein digesting enzymes called proteases
-functions to degrade and recycle damaged, denatured or abnormal proteins
-hydrolyzes peptide bonds of proteins tagged with ubiquitin to recycle amino acids, cell can have many

30
Q

Mitochondria

A

-sausage shaped with double membrane
-outer membrane: smooth
-inner membrane: folded folds called cristae
-center= matrix (fluid)
-aerobic cellular respirations occurs on surface of cristae where glucose is catabolized creating CO2 and H2O waster to convert ADP into ATP
-mitochondria supply most of cell’s energy (~95%: 2ATP per glucose w/o mitochondria 36 ATP per glucose with)
-have their own DNA
-can replicate independent of the cell
-mitochondrial DNA is maternal

31
Q

Nucleus

A

-control center of cell: directs proteins synthesis (proteins are responsible for structure and function of cell)
-contains DNA: genetic material
-most cells have one, exceptions skeletal muscle (many), RBCs (none)
-surrounded by nuclear envelope: double membrane, outer layer connected to ER
-has nuclear pores with regulator proteins that control exchange of molecules between cytoplasm and nucleus
-inside is DNA floating in nucleoplasm with nucleotides, RNA and protein enzymes
-in non dividing cells DNA is loose called chromatin
-open form of DNA allows access to information to direct protein synthesis

32
Q

DNA

A

-inside a nucleus is DNA floating in nucleoplasm with nucleotides, RNA and protein enzymes
-in non dividing cells DNA is loose called chromatin
-open form of DNA allows access to information to direct protein synthesis
=DNA in chromatin is organized into nucleosomes:DNA wound around histone proteins

33
Q

nucleosomes

A

prevent tangling and breakage and reduce amount of space DNA takes up

34
Q

nuclear division

A

chromatin is tightly wound into individual visible bundles of DNA called chromosomes (23 pairs in humans)

35
Q

Genetic Informations

A

-DNA contains genes
Genes = functional units of heredity
-encode for a product: RNA or protein Humans have ~30 thousand potential genes (most encode enzymes for metabolism)
-this is only 1.5% of total DNA
-remainder is involved with control of genes, some appears to be junk (25%)
-noncoding parts of DNA (non-genes) is highly variable one person to next
-variability allows for identification of an individual by DNA fingerprinting
-in order for a gene to be expressed (used to make a product) it must be unwound from the histone proteins so it can be read
-disassembly of the nucleosomes and
unwinding of the DNA to copy the
information is called gene activation

36
Q

Genetic Code

A

-language of the DNA that is read off a gene in order to assemble a protein
-3 bases of DNA = 1 codon
-each codon gives the instructions for one amino acid
-a gene= all the codons for all the amino acids in one protein in the correct order with control regions

37
Q

Transcription

A

-making an RNA copy of a DNA gene
-occurs in nucleus

38
Q

Translation

A

=making a protein using the mRNA blueprint
-occurs in the cytoplasm on free ribosomes or on fixed ribosomes

39
Q

Components that assemble in cytoplasm

A

-two ribosomal subunits
-mRNA
-tRNAs carrying amino acids

40
Q

The life cycle of a cell

A

-life span cell depends on type of cell
-all cells eventually die
-some cells must divide to make cells to replace dying cells: function of stem cells -to divide, DNA must be replicated and equally distributed between the stem cell and new daughter
-most cells spend very little time dividing in an adult instead are performing cellular functions

41
Q

Mitosis

A

=nuclear division
-Once G1 phase S phase and G2 phase of interphase are complete mitosis begins

42
Q

apoptosis

A

controlled to cell death, lysosomes are defused to prevent damage to other cells

43
Q

The cell cycle

A
  1. Interphase: period of time that a cell performs its normal functions
    -if a cell never divides, it remains in G0 phase of interphase
    -if the cell is preparing to divide, it will go through 3 stages in interphase:
    A. G1 phase: cell doubles organelles and synthesizes enough cytoplasm for two cells
    B. S phase: cell duplicates DNA
    C. G2 phase: copious protein synthesis: cell generates enough enzymes for two cells, centrioles are replicated
44
Q

DNA Replication

A

-S phase of interphase
-only performed by cells preparing for division
-will be followed by mitosis

A&P 1 (21 decks)

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