Cellular mechanics and Communication Flashcards by natalia matteo

Two processes involving manufacturing
a) respiration and expiration
b) active and passive breathing
c) transcription and translation
d) DNA and RNA

Transcription and translation

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What is the first step of DNA based gene expression?

Transcription

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Define transcription

A segment of DNA copied into RNA (mRNA) by enzyme RNA polymerase

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During transcription a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand called a ______ _______

primary transcript

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Adenine (A) bonds to ____________________ by 2 hydrogen bonds

Thymine (T)

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Guanine (G) bones to ________________ by 3 hydrogen bones

Cytosine (C)

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Steps of transcription

1) RNA polymerase binds to promoter DNA
2) RNA polymerase creates bubble, separating the two strands of the DNA helix
3) RNA polymerase adds RNA nucleotides
4) RNA sugar-phosphate backbone forms an RNA strand
5) RNA further processed (polyadenylation, capping, and splicing)
6) RNA remains in nucleus or leaves cytoplasm through nuclear pore complex

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Gene splicing

Introns removed - review

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Stages of Translation

1) mRNA is decoded in the ribosome decoding center to produce a specific amino acid chain, or polypeptide
2) polypeptide later folds into an active protein and performs its functions in the cell
3) ribosome facilitates decoding by inducing the binding of complementary tRNA anticodon sequences to mRNA codons
4) tRNAs carry specific amino acids that are chained together into a polypeptide as the mRNA passes through and is read by the ribosome

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Codons

hidden messages within nucleotides sequencues that tell a particular amino acid signal to start or stop

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Step 1 of Translation: Initiation

ribosome assessmbles around target mRNA
- first tRNA attached at the start codon

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Step 2 of Translation: Elongation

tRNA transfers amino acid to tRNA corresponding to next codon
- ribosome then translocates to next mRNA codon to continue process, creating amino acid chain

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Step 3 of Translation: Termination

when a peptidyl tRNA encounters stop codon
- ribosome folds the polypeptide into final structure

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Cell division

process by which parent cell divides into 2 of more daughter cells

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In eukaryotes, there are two distinct types of ______________

cell division

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Types of cell division in eukaryotes

Mitosis and meiosis

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Each daughter cell is genetically identical to the parent cell

mitosis (vegetative division)

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Number of chromosomes in daughter cells is reduced by 1/2 to produce haploid gametes

Meiosis

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__________ accounts for a small part of the duration of a cell cycle

Mitosis

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Prophase

chromosomes condense and become visible
- centrosomes move toward opposite poles

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Prometaphase

Kinetochores appear at centromeres
- mitotic spindle microtubules attach to kinetochores

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Metaphase

chromosomes meet at middle
- each sister chromatid is attached to spindle fiber from opposite poke

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Anaphase

centromeres split in two
- chromosomes are pulled toward opposite poles

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Telophase

chromosomes arrive at opposite poles & decodense
- nuclear envelope surround each set of chromosomes
- mitotic spindle breaks down
- spindle fibers continue to push poles apart

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Cytokinesis

2 separate entities

Types of signaling molecules a) proteins b) small peptides c) amino acids d) nucleotides e) steroids/retinoids f) dissolved gases g) all of the above

All of the above

What are the types of signaling? a) embryonic signaling b) paracrine signaling c) endocrine signaling d) synaptic signaling e) A, B, and C f) B, C, and D

Paracrine signaling, endocrine signaling, and synaptic signaling

Paracrine signaling

local action only fast acting growth factors, clotting factors

Endocrine signaling

secreted in blood stream for widespread or distant targeting very slow acting pineal, pituitary, thyroid, pancreas, etc. recognized by receptors

Synaptic signaling

secretion at specialized cell to cell contacts (synapses) very fast acting used only by electrically excitable cells (neurons and muscle cells)

In almost all forms of signaling, the signal molecule is ___________ from the secreting cell via a process known as ____________

released; exocytosis

Long term connections can be classified into functional groups such as: a) inhibitory junctions b) tight junctions c) desmosomes/hemidesmosomes d) gap junctions

B, C, and D

Impermeable junctions preventing molecules from passing through the intercellular space

tight junctions / occluding junctions

binding adjacent cells together like a molecular "velcro" and help form an internal tension-reducing network of fibers

desmosomes / anchoring junctions

allowing ions & small molecules to pass for intercellular communication

gap junctions / communicating junctions

roles of tight/occluding junctions

1) form leak-proof seals 2) create cell polarizations along membranes

which junction(s) are most prominent in tissues subject to mechanical stress

desmosomes/hemidesmosomes and adherents junctions / anchoring junctions

which junction is comprised of an intracellular plaque that is anchored to IF or actin and cadherin

desmosomes junctions / anchoring junctions

What is the difference between desmosomes and hemidesmosomes

hemidesmosomes are comprised to an intracellular plaque which is anchored to an ECM protein

How are desmosomes and hemidesmosomes similar

Anchored intracellularly to actin or IF cytoskeleton

What do gap junctions comprise of

junctional complex (connexon)

T/F Permeability of communicating junctions is affected by environmental influences.

True

Extracellular matrix is a network of _______________

macromolecules

The extracellular matrix is a network of _______________

macromolecules

What do the macromolecules include?

1) glycosaminoglycans (hydrated gels) 2) fibrous proteins (structural and adhesive)

What are some basic tissues

epithelium connective tissue muscle tissue nerve tissue

What determines the classification of epithelium

1) shape 2) # of layers 3) cell specializations

Flat and one layered

simple squamous

Square and one layered

Simple cuboidal

Tall and one layered

Simple columnar

Skin

Stratified squamous

An epithelium that is not common

stratified cuboidal

In some parts of the respiratory system

stratified columnar

What are some connective tissues

a) fibroblast b) collagen fiber c) macrophage d) elastic fiber

What is the simplest and most widely distributed connective tissue found in the body ?

areolar tissue

What are the principle cell precursor that are always present and give the matrix its gel-like qualities

fibroblasts

What is the principle cell that has differentiated fibroblasts that maintain fibers

fibrocytes

What cells found in connective tissues hold fat storage

adipocytes

What cells found in connective tissues are stem cells of fibroblasts, macrophages, etc?

mesenchymal cells

What cells found in connective tissues are fixed or free scavengers

macrophages

What cells found in connective tissues contain histamine and heparin to enhance immune response

mast cells

Skeletal muscles has a ___________ apperance

striped

Cardiac muscles has a _______________ apperance

looser

Smooth muscles have a _______________ apperance

wavy

Nervous muscles have _______________

many -cytes that relate to synapses