Cells and Tissues

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Cells and TissuesChapter 3

Visualizing A & P


Plasma Membrane


TransportInteractions Animations

• Transport Across the Plasma Membrane

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Pumps Use energy from ATP hydrolysis Sodium-potassium pump

Hydrolysis=Brk apart molecules w/H2O


Parts of a Cell


Ribosomes Made from RNA and proteins in nucleolus of

cell nucleus Locations in cell

Associated with the rough endoplasmic reticulum In mitochondria Free floating in cytosol

Function: protein manufacturing


Ribosomes


Proteins Made of long chains of subunits called amino

acids 20 different kinds of amino acids that humans use Typical protein has ~100 amino acids linked in

chains

Chemical properties for a specific protein depend on its structure


Protein – 3 Dimensional Structure The actual sequence of amino acids in a protein is called =

primary sequence The coiling and bending determine the

proteins = secondary structure In most proteins, entire chain folds into

a compact mass called=

tertiary structure When two or more folded proteins

combine to form clusters, the mix of proteins form a =

quaternary structure


Protein -3 Dimensional Structure Ex. Structure of the Protein Insulin exists in 4

Levels


Protein Function: Structural role in organisms

Cartilage and tendons made of protein called collagen

Matrix of our skin and bones made of protein Protein called keratin forms horns on rhinos,

feathers on birds, and hair on humans Acts as an enzyme

Enzymes -increase rate a chm rxn occurs Most chm rxns nessessary for growth, movement,

and other body activities would not take place without enzymes


Proteins made in Complex Process Like building a house…

Need set of plans –architectural firm Plan transcribed into blueprints which are taken

to home site Workers bring materials according to blueprints Essentially translating information in blueprint

into final product


Protein Synthesis

Transcription (Nucleus) Instructions for creating protein conveyed from

DNA to messenger RNA (mRNA) Translation (Ribosomes)

mRNA carries instructions to ribosomes, and with the help of transfer RNA (tRNA), the appropriate amino acids bind together in a specific sequence to create a protein


Transcription

Preparing for transcription In the nucleus, DNA encodes instructions for

protein synthesis Nucleotides in DNA sequence specifies which

amino acids in which order will be in the protein


Transcription Transcription

Codon = 3 nucleotides ‘codes’ for an amino acid DNA cannot leave the nucleus, therefore mRNA is

then made as a copy of the DNA in the nucleus = transcription RNA polymerase bind to DNA at the promoter region RNA polymerase moves along DNA strand, making a copy,

as mRNA nucleotides pair with complimentary DNA nucleotides

At the terminator region, RNA polymerase stops, falls off the DNA, and releases the mRNA that was made

The mRNA has a nucleotide sequence that is complimentary to the DNA sequence, and has ‘transcribed’ instructions for the amino acid order to make the specific protein

The mRNA leaves through nuclear pores and goes to the ER


Transcription


Translation

Preparing for translation Ribosomes attach to the mRNA at the start

sequence (AUG) and move along mRNA strand tRNA bound to specific amino acids enter the

ribosome Anticodons on tRNA are complimentary to the

codon on the mRNA


Translation Translation

Anticodons of the tRNA pair up with appropriate mRNA codons

Peptide bond formation occurs through dehydration synthesis between amino acids in the ribosome

Empty tRNA leaves and process repeats until the protein is made

Ribosome reaches a stop codon in mRNA (UGA, UAG, UAA)

Ribosome breaks apart and releases the synthesized protein

Dehydration Synthesis –removing a H2O molecule to join atoms together and make a molecule


Translation

Covalent Chemical Bond formed between two molecules when carboxyl group (COOH) of 1 molecule

rxts with amino grp (NH2) of other molecule causing release of H2O (Dehydration Synth)


Protein SynthesisInteractions Animation

• Protein Synthesis



Cell Cycle Interphase

G1 = growth phase Protein synthesis

S = DNA replication G2 = another growth phase

Protein synthesis

Mitosis Prophase Metaphase Anaphase Telophase


Cell Division Mitosis

Somatic cell division; diploid cells (23 pairs of chromosomes = 46 chromosomes)

Meiosis Gamete cell division; haploid cells (23 unpaired

chromosomes)



Mitosis


Mitosis


Mitosis


Mitosis


Mitosis


Mitosis


Meiosis


Mitosis vs. Meiosis


Cell DivisionInteractions Animation

• The Cell Cycle and Division Processes


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Cells and Tissues