Anatomy – Cell Biology Review

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BASIC CELL COMPOSITION Plasma Membrane

(Cell Membrane) - surrounds cell and gives it form

Cytoplasm - consists of: 1) cytosol: 2) organelles:

Nucleus - contains DNA (deoxyribonucleic acid)

PLASMA MEMBRANE

Structure: double layer of phospolipids proteins glycoproteins glycolipids

Selectively permeable What are some benefits

and some disadvantages of having a selectively permeable membrane?

CYTOPLASMIC ORGANELLES A. Mitochondria

        * make ATP (adenosine triphosphate)         * contains its own DNA    

CYTOPLASMIC ORGANELLES - cont B. Ribosomes -

involved in protein synthesis (synthesis = production)         * two kinds: Free ribosomes or ribosomes attached to Rough ER

CYTOPLASMIC ORGANELLES - cont C. Endoplasmic Reticulum (ER) - a network

of tubules used to transport & synthesize         (produce) materials 1) Rough ER - has ribosomes on walls

            * synthesizes & distributes proteins 2) Smooth ER - has no ribosomes

            * synthesizes lipids, mainly steroids              

CYTOPLASMIC ORGANELLES – cont. D. Lysosomes - contain digestive enzymes

  E. Centrioles - involved in cell division

NUCLEUS     Contains DNA (deoxyribonucleic acid) --

when cell is NOT dividing, DNA in the form of chromatin

Some nuclei have a nucleolus         * makes the "parts" that form ribosomes

CELL CYCLE    Cells divided into:

1) Sex cells (sperm and oocytes) 2) Somatic cells (all other cells)

Cell cycle subdivided into 2 phases: 1) Interphase - cell not dividing

            * DNA is duplicated during this time 2) Mitosis (cell division for somatic cells)

            or Meiosis (cell division for sex cells)

MITOSIS

1) Prophase DNA in form of double-stranded chromosomes double-stranded (duplicated) chromosomes consist of 2 chromatids

joined at a centromere (chromatid = each half of the duplicated chromosome) spindle fibers go from centrioles to chromatids breakdown of nuclear membrane

   

    2) Metaphase ("Middle")         * chromosomes along center (middle) of cell  

Mitosis – cont.

3) Anaphase ( "Apart") chromatids split apart at centromere each set of chromatids (now called single-stranded chromosomes)

pulled to opposite ends of cell  

4) Telophase ("Two") nuclear envelope reforms nucleolus reappears cleavage furrow develops cytokinesis occurs

   Cell now re-enters Interphase

Meiosis - Def: cell division where gametes (sperm cells or oocytes) are formed -

 Differences between mitosis and meiosis:1) Mitosis produces 2 cells containing 46 chromosomes (23 pairs)

            * daughter cells identical to original (parent) cell             * cells are diploid: they have 2 of each chromosome

          2) Meiosis produces 4 cells containing only 23 chromosomes

            * daughter cells genetically different from parent cell             * these cells have a haploid number of chromosomes (only 1 of each

                chromosome)     -- Start off with one cell that has 23 pairs of chromosomes

        * one set of chromosomes came from MOTHER, the other from FATHER  

    -- Interphase: DNA is duplicated         * DNA will form double-stranded chromosomes

        * cell now contains 23 pairs of double-stranded (duplicate) chromosomes  

Mitosis vs. Meiosis

1) Mitosis produces 2 cells containing 46 chromosomes (23 pairs) daughter cells identical to original (parent) cell cells are diploid: they have 2 of each chromosome

2) Meiosis produces 4 cells containing only 23 chromosomes daughter cells genetically different from parent cell these cells have a haploid number of chromosomes (only 1 of each

chromosome) Start off with one cell that has 23 pairs of chromosomes

one set of chromosomes came from MOTHER, the other from FATHER  

    -- Interphase: DNA is duplicated         * DNA will form double-stranded chromosomes

        * cell now contains 23 pairs of double-stranded (duplicate) chromosomes

Meiosis

1st meiotic prophase, homologous chromosomes pair up    

Crossing Over: process by which genetic material is exchanged between homologous chromosomes

occurs during 1st prophase  

Cell finishes 1st meiotic division, producing 2 daughter cells daughter cells each have 23 double-stranded chromosomes (each

chromosome consists of 2 chromatids) parent cell had 23 PAIRS of chromosomes, but daughter cells have only 23

chromosomes  Cells go through 2nd meiotic division:

4 cells produced, each with 23 single-stranded chromosomes (each chromosome has only 1 chromatid now)

these 4 cells are gametes  

For EXAM 1

Apendix A: p. 564 Misc., p. 565 Prefixes A-C p. 566 Suffixes A-C

Handout p. 30-31 Anatomy of a Generalized Cell (Structure, Location, Function)

Planes of Reference and Directional Terms