Test 2 A&p

Front 1

Cytoplasm

Back 1

• Located between plasma membrane and nucleus
  
• The site of many chemical reactions
  
• Reactions provide the building blocks for cell maintenance, structure, function, and growth
  

Front 2

Cytoplasm is composed of...

Back 2

• Cytosol -- Water with solutes (protein, salts, sugars, etc.)
  
• Organelles -- Metabolic machinery of a cell, each with specialized function. Either membranous or nonmembranous
  
• Inclusions -- vary with cell type; e.g., glycogen granules, pigments, lipid droplets, crystals, etc.
  

Front 3

Nonmembranous

Back 3

• Cytoskeleton
  
• Centrioles
  
• Ribosomes
  

Front 4

Membranous

Back 4

• Surrounded by a plasma membrane
  
• Endoplasmic reticulum (RER and SER)
  
• MItochondria
  
• Golgi apparatus
  
• Peroxisomes
  
• Lysosomes

Front 5

Membranes allow

Back 5

Crucial Compartmentalization

Front 6

Cytoskeleton

Back 6

• Network of protein filaments throughout the cytosol
  
• A scaffold-like structure that provides structural support for shape and movement.
  
• Three types:
  

1. Microfilaments
   
2. Intermediate filaments
   
3. Microtubules
   

Front 7

Microfilaments

Back 7

• Thinnest of cytoskeletal elements
  
• Involved in cell motility, change in shape, endocytosis and exocytosis
  

Front 8

Intermediate filaments

Back 8

• Tough, insoluble, rope like protein fibers
  
• Resist pulling forced on cell; attach to desmosomes

Front 9

Microtubules

Back 9

• Largest of cytoskeletal elements; dynamic hollow tubes; most radiate from centrosome
  
• Determine overall shape of cell and distribution of organelles
  
• Mitochondria, lysosomes, secretory vesicles attach to microtubules; moved throughout the cell by motor proteins.
  

Front 10

Centrosome

Back 10

• Located near the nucleus
  
• Generates microtubules; organizes mitotic spindle (used for cell division)
  
• Contains paired centrioles -- barrel-shaped organelles formed by microtubules
  
• Centrioles form basis of cilia and flagella
  

Front 11

Cilia

Back 11

Short, hair-like projections from the cell surface, move fluids along a cell surface

Front 12

Flagella

Back 12

Longer than cilia, move an entire cell; example for human is the sperm cell's tail

Front 13

Ribosomes

Back 13

• Granules containing protein and rRNA
  
• Site of protein synthesis
  

Front 14

Free ribosomes

Back 14

Synthesize soluble proteins that function in cytosol or other organelles

Front 15

Membrane-bound ribosomes

Back 15

• Found in rough ER
  
• Synthesize proteins to be incorporated into cell membranes, lysosomes, or exported from cell.
  

Front 16

Endoplasmic Reticulum

Back 16

• Network of membranes in the shape of flattened sacs or tubules
  
• Rough ER
  
• Smooth ER
  

Front 17

Rough ER

Back 17

• A series of flattened sacs connected to the nuclear envelope
  
• Surface is studded with ribosomes that produce various proteins
  

Front 18

Smooth ER

Back 18

• A network of membrane tubules
  
• No ribosomes
  
• Synthesizes fatty acids and steroids, detoxifies certain drugs
  

Front 19

MItochondria - the "powerhouse" of the eukaryotic cell

Back 19

• Generate the majority of ATP in human cells
  

Use oxygen and products of glycolysis to perform aerobic cellular respiration

• More abundant in physiologically active cells:
  

muscles, liver, and kidneys

• Have inner and outer mitochondrial membranes that are similar in structure to the plasma membrane

Creates 2 separate compartments in the mitochondria
Cristae - the series of folds of the inner membrane
Matrix - the large central fluid-filled cavity

• Can self-replicate during times of increased cellular demand or before cell division
• Contain their own DNA, RNA, and ribosomes

Suspected that they were once prokaryotic cells that formed a symbiotic relationship with eukaryotic ones

• Inherited from your mother only

Front 20

Golgi complex

Back 20

• consists of 3-20 flattened, membranous sacs called cisternae.
  
• The post office of the cell
  
• Modifies, sorts, and packages proteins made by the RER for transport to different intra- and extra-cellular destinations.
  

---- Products are transported using various types of vesicles.

Front 21

Lysosomes

Back 21

Vesicles that form from the Golgi complex and contain powerful digestive enzymes

Front 22

Peroxisomes

Back 22

• Smaller than lysosomes
  
• Detoxify several toxic substances such as alcohol
  
• abundant in hepatocytes (liver cells)
  

Front 23

Proteasomes

Back 23

• Continuously destroy unneeded, damaged, or faulty proteins
  
• Found in the cytosol and the nucleus
  

Front 24

Nucleus

Back 24

• Spherical or oval shaped structure
  
• Usually most prominent feature of a cell
  
• Contains the DNA of eukaryotic cell
  
• Contains the DNA of a eukaryotic cell
  

Front 25

Nuclear Envelope

Back 25

A double membrane that separates the nucleus from the cytoplasm

Front 26

Nuclear pores

Back 26

• Numerous protein based openings in the nuclear envelope
  

-- control movement of substances between nucleus and cytoplasm

Front 27

Nucleolus

Back 27

Spherical body that produces ribosomes

Front 28

Chromosomes

Back 28

long molecules of DNA combined with protein molecules

Front 29

Genes

Back 29

• The cell's hereditary units that are found chromosomes
  

--- control activities and structure of the cell

Front 30

Gene Expression

Back 30

The flow of genetic information in a cell is DNA

--> RNA --> Protein

---- Occurs in 2 steps:

1. Transcription (DNA --> RNA)

2. Translation (RNA --> PROTEIN)

Front 31

Transfer RNA: tRNA

Back 31

• Each type of tRNA is bound to a specific amino acid.
  

45 different types of tRNA molecules

--- Some specific amino acids are bound to more than one type of tRNA molecule

• Carry amino acids to the ribosome and has a region with an anticodon (3 nucleotide sequence on the tRNA) that is complementary to a codon on the mRNA molecule
  

--- Codons are 3 nucleotide sequences found on the mRNA

• The sequence of the 3 nucleotides in a codon determines the appropriate tRNA molecule that will dock with the mRNA along with it's particular amino acid

The amino acid will be added to the growing peptide chain by the ribosome.

Front 32

A protein is put together one amino acid at a time

Back 32

• The ribosome attaches to the mRNA at the promoter region
  
• Ribosome facilitates the docking of tRNA anticodons to mRNA codons
  
• When two tRNAs are adjacent, a bond is formed between their amino acids.
  
• Forms a peptide chain of amino acids
  
• The ribosome then moves to the next codon on the mRNA to continue docking complementary tRNAs and adding amino acids until a stop codon is reached.
  
• Protein product may be modified before it is allowed to fold and form final 3D shape.
  

Front 33

Somatic cell division - mitosis

Back 33

• The cell cycle is a sequence of events in which a body cell performs its normal functions, duplicates its contents, and divides in two
  
• Human somatic cells contain 23 pairs (2 sets) of chromosomes
  

somatic (normal body) cells contain two sets of chromosomes and are called diploid cells

23 are from your father (paternal), and 23 are from your mother (maternal)

Total = 46

• The two chromosomes (maternal and paternal) that make up each pair are called homologous chromosomes (homologs)
  

Front 34

Interphase

Back 34

• The cell is not dividing
  
• Consists of three phased G1, S, and G2
  

G1: cell grows, organelles duplicate

S: DNA replicates

G2: cell makes proteins needed to complete mitosis

-- A G0 phase also exists

Front 35

Mitotic Phase

Back 35

• consists of a nuclear division (mitosis) and a cytoplasmic division (cytokinesis) to form two identical cells
  
• Each contain 46 chromosome in its nucleus
  

Front 36

S Phase DNA Replication

Back 36

• DNA polymerase: the enzyme that replicates DNA
  
• It moves along the length of the unwound DNA and helps form the new strands
  
• Covalent bonds are formed between new complementary nucleotides added to the growing strand
  
• Nucleotides are added to produce a new strand based on the old one
  
• Hydrogen bonds hold the nitrogenous bases of the nucleotides in the old and new strands together
  
• Result is two identical DNA polymer daughter molecules, each with one parental strand and one new strand (semiconservative replication)
  
• DNA polymerase has a proofreading function to limit errors, mutations, in matching
  

Front 37

Mitotic Cell division

Back 37

• Produces clones
  
• Essential for body growth and tissue repair
  
• Occurs continuously in some cells
  

--- skin, intestinal lining, etc.

• None in most mature cells of nervous tissue, skeletal muscle, and cardia muscle
  

--- Repair made with fibrous tissue

Front 38

Mitotic cell division -- Consists of 4 stages

Back 38

1. Prophase
   
2. Metaphase
   
3. Anaphase
   
4. Telophase
   

-- Usually, but not alway, followed by cytokinesis.

Front 39

Prophase

Back 39

The chromatin fibers (DNA's normal form in the nucleus) change into chromosomes

Front 40

Metaphase

Back 40

microtubules align the centromeres of the chromatid pairs at the metaphase plate.

Front 41

Anaphase

Back 41

The Chromatid pairs split at the centromere and move to opposite poles of the cell; the chromatids are now called chromosomes.

Front 42

Cytokinesis: Cytoplasmic Division

Back 42

• Division of a cell's cytoplasm to form two identical cells
  
• Usually begins in late anaphase
  
• The plasma membrane constricts at its middle, forming a cleavage furrow
  
• The cell eventually splits into two daughter cells
  
• Interphase begins when cytokinesis is complete.
  

Front 43

Telophase

Back 43

Two identical nuclei are formed around the identical sets of chromosomes now in their chromatin form.

Front 44

Reproductive Cell Division

Back 44

• During sexual reproduction, each new organism is the result of the union of two gametes (fertilization), one from each parent.
  
• Meiosis
  
• Haploid cells
  
• Fertilization restores the diploid number of chromosomes (46)
  

Front 45

Meiosis

Back 45

• Reproductive cell division that occurs int he gonads (ovaries and testes) that produces gametes with half the number of chromosomes.
  
• Occurs in two successive stages: meiosis I and meiosis II.
  
• Each of these two stages has 4 phases:
  

1. Prophase
   
2. Metaphase
   
3. Anaphase
   
4. Telophase
   

Front 46

Haploid cells

Back 46

Gametes contain a single set of 23 chromosomes

Front 47

Meiosis I

Back 47

• begins with a diploid cell (23 pairs of chromosomes) and ends with two cells having the haploid number (23 chromosomes) of chromosomes
  

Front 48

Meiosis II

Back 48

• each of the two haploid cells divides, and the net result is four haploid gametes that are genetically different from the original diploid starting cell.