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College Biology #1





College Biology Review 1

9/8

Scientific Method- A series of steps for answering questions. Can vary greatly; hypothetico- deductive method is the base of most.

Scientific Theory- An answer to an experiment (there can be many of these from the same experiment).

Biogenesis- The development of life from pre- existing life.

9 Unifying Themes of Biology:

1. A Hierarchy of Organization- levels of structure

2. Emergent Properties- steps in evolution

3. Cellular Basis of Life- all organisms are composed of cells

4. Heritable Information- DNA/RNA code for life

5. Feeling for Organisms- familiarity with research

6. Correlation Between Structure and Function- form fits purpose

7. Interaction of Organisms with their Environment- codependency

8. Unity in Diversity- organization of species

9. Evolution- core of biology

Hierarchy of Biology-

1. Atoms

2. Molecules

3. Organelles

4. Cells

5. Tissues

6. Organs

7. Organ systems

8. Organisms

9. Population

10. Community

11. Ecosystem

Emergent Properties are advantageous and help with natural selection. Ex. Bicycle to Motorcycle: Emergent property is the engine

Prokaryotic vs. Eukaryotic

Prokaryotic- Lacks membrane- bound organelles (has only ribosomes). Found in the Monera Kingdom. Smaller than Eukaryotic cells.

Eukaryotic- Has membrane- bound organelles. Found in all kingdoms but Monera.

9/11

Darwin’s theory of “descent with modification”, or evolution, is one of the rudiments of biology. Evolution is the explanation for emergent properties in all organisms.

Inductive Reasoning- Using specific information to make generalizations

Deductive Reasoning- Using generalizations to make specific conclusions

Holism- A principal that believes taking a living system apart interferes with meaningful explanations and processes.

Reductionism- Reducing complex systems to simpler components that are more manageable to study.

History of Cells 9/15

Hooke- 1665 looked at a piece of oak bark at 30x and saw little boxes. Labeled them cells. Believed they only pertained to the oak tree.

Leeuwenhok (late 1600s)- looked at single-celled pond organisms, blood, and sperm cells under 300x magnification. Gave us large amounts of data

Schleiden and Schwann 1839- using previous data and their own theorized that all living things are made of cells. This became the basis of the cell theory, which later expanded to say all cells come from previous cells (biogenesis).

Microscopes- helped us to understand cells

Light microscope- visible light focused on a specimen with a lens

Electron microscope- uses electron beams (shorter wavelength than light)

TEM- Transmission Electron Microscope- thin section of specimen

SEM- Scanning Electron Microscope- scanning surface of specimen

9/16

Cytoplasm- all the space between the cell wall and the nucleus

Cytosol- the liquid in the cytoplasm

Mitochondria- produces ATP for cellular processes. Look like kidneys

Lysosome- Digest macromolecules, recycle cell waste and program cell destruction when necessary

Rough Endoplasmic Reticulum (ER)- makes proteins for export and makes more membranes

Smooth ER- makes lipids and carbohydrates, detoxifies drugs, stores calcium

Nucleus- contains most of the genes that control the cell

Ribosomes- makes proteins, can be free floating or attached to a membrane

Nuclear membrane- phospholipid bilayer that surrounds the nucleus

Plastids- a family of closely related plant organelles

Chloroplasts- chlorophyll containing plastids, site for photosynthesis

Chromoplasts- plastids containing pigments other than chlorophyll

Amyloplasts- colorless plastids that store starch

Microtubules- solid rods that aid in muscle contraction and support

Microfilaments- used during cell division and found in cilia and flagella

Food vacuole- formed by phagocytosis by collecting food from outside the cell

Vesicles- transport vehicles; from ER to golgi to cell membrane, etc.

Golgi apparatus- modifies, sorts and stores products received from the ER

Cell wall- found only in plant cells, prevents too much water uptake

Cilia- work like oars fro movement of cells

Flagella- often singular structure with undulating motion to move cell

Contractile vacuole- stores molecules and absorbs water

Central vacuole- stores molecules and absorbs water

Peroxisome- microbodies that contain specialized teams of enzymes

Cytoskeleton- network of fibers; forms framework for support and movement

Energy transducers (mitochondria or chloroplasts) make food for the cell. The endomembrane system uses the energy for cell functions

9/17 Animal Cells Plant Cells -cell membrane -cell membrane and wall -have lysosomes -have plastids -small vacuoles -large vacuoles

9/18

Fluid membrane- held together by weak bonds- phospholipid bilayer

Hydrophilic head- positive charge- attracted to water

Hydrophobic tail- negative charge- moves away from water

Passive Transport

Lipids and proteins float around in membrane-

1. Marker proteins- identify cell (name tag)

2. Transport proteins- channels/ bridges to help things get across membrane- called facilitated diffusion

3. Receptor proteins- can cause reaction within cell or on cell membrane

Permeability of membrane/lipid bilayer- Non- polar items pass easily- polar items have trouble. Water is polar, so hydrophilic heads move apart to let non-polar items through

Diffusion- high to low concentration

Osmosis- the diffusion of water

Active Transport

Active transport requires energy. Particles move from low to high concentration.

Ion transport- nerve cells (axon)

Differential charge- different sides of a cell have a different charge and move information down the nerve

Pro transport- single ATP powered pump indirectly drives other active transport

Solutions

Hypo- lower concentration outside the cell than inside

Hypotonic- molecules want to move out of the cell

Hypoosmotic- molecules can’t move- water moves in to dilute and cell swells

Iso- same

Under isotonic and isoosmotic conditions nothing happens. This is what the cell wants.

Hyper- higher concentration in the cell than in its environment

Hypertonic- molecules want to move in the cell

Hyperosmotic- water moves out of cell to dilute, causing cell to shrink

Exocytosis- taking wastes and other products outside the cell

Endocytosis- taking products inside the cell

Pinocytosis- taking liquids in

Phagocytosis- taking solids in

Cellular Respiration 9/22

Opposite of photosynthesis

Oxidation- lose electrons

Reduction- gain electrons

Redox Reaction- equation has oxidation and reduction

3 Steps of Cellular Respiration

1. Glycolysis- occurs in cytosol, starts with 6 carbon molecule, splits into two 3-carbon chains, or pyruvates. Oxidizes sugar. Ends with two ATPs

2. Kreb Cycle- occours in mitochondria’s matrix- ends with two ATPs and sugar is now fully oxidized

3. Electron Transport Chain (ETC)- takes place in inner membrane (between matrix and cristae in mitiochondria). Most important step; creates 32-34 ATPs and O2 and H20.

3. Fermentation- No oxygen environment. First two steps occur without oxygen. Whole process makes 6 ATPs

Mitochondria have their own DNA and ribosomes (like a mini- cell)

Photosynthesis 9/23

Opposite of cellular respiration

CO4 + H20 + energy à C6H12O6 + O2

Only autotrophs can do this (they can do cellular respiration too)

2 stages:

1. Light Reactions- light energy becomes chemical energy. Makes 6 ATPs, turns H20 to O2, takes place in the thylakoid membrane.

2. Calvin Cycle- occurs in stroma, uses 9 ATPs, CO2 turns to glyceraldehyde phosphate (PO4-c-c-c) and 2gps to sugar.

I see the light! 9/24

________________________________________________

Infared <- R O Y G

B I V -> Ultraviolet

750 nm Visible Spectrum 380 nm

Spectrophotometer- measures levels of absorption

Carotene- yellow-orange- no molecules that want to H- bond

Xanthophyll- yellow- contains O2, so H- bonds

Chlorophyll A- blue- green- more soluble, contains O2 and N, H- bonds

Chlorophyll B- olive- green- contains O2 and N, H- bonds

Chlorophyll A is used in photosynthesis. The others convert/ transfer light energy to CA

Photorespiration- consumes O2

- Plants take in CO2 and give off O2

- Found in desert plants- C4 and CAM

- Plants work twice as hard

- Like fermentation, is an oddity, evolutionarily upsetting (create less ATPs)

Reproduction of Cells- General 9/29 and 9/30

- Not all cells regenerate. Nerve cells, for example, don’t have this ability

- The ability to reproduce distinguishes living organisms from non-living organisms

Unicellular- division of the cell produces an entire organism. Called binary fission. Occurs in monera kingdom only.

1. Bacterium grows to twice its normal size

2. Chromosomes are copied and each copy attaches to plasma membrane

3. Plasma membrane pinches inward to divide the cell

4. New cell wall is deposited between daughter cells

Multicellular- cell division- growth and development of fertilized egg and replacement of dead/ damaged cells

1. Interphase- 90% of a cell’s time is spent here

A. G growth

B. S synthesis

C. G2 growth and leads into mitosis

2. Mitosis (m stage) compose of seven? smaller stages

a. Prophase- Chromosomes copy? Each other

b. Prometaphase- nuclear envelope fragments, macrotubules w/ spindle fibers go to poles

c. Metaphase- (Kinetochore)? Line up at metaphase plate (equator)

d. Anaphase- chromosomes move toward poles centromeres first

e. Telophase- microtubules break down, cleavage furrows appear and nuclear envelopes begin to form

f. Cytokinesis- two separate cells w/ own nuclear envelopes

- Cell division is not just a simple pinching in half, but a complex process of passing along the genome, from one cell generation to the next

- Genome- all of the genes carried by a set of chromosomes

Bacterial Replication

a. Prokaryotes reproduce by binary fission

b. Bacterium grows to twice initial size

c. Chromosomes are copied and each copy is attached to the plasma membrane

Eukaryotic Chromosomes

d. Genetic material is precisely, equally divided between daughter cells in the form of chromosomes

e. Chromatin- long, thin fiber of DNA that is folded to form chromosomes

f. Chromosomes- threadlike structures composed of DNA and protein that are distributed during mitosis

g. All somatic (body) cells have the same number of chromosomes (46 human)

h. Sperm and ova (sex cells) have half the number of chromosomes of somatic cells (23 human)

i. Mitosis- nuclear division

j. Cytokinesis- division of cytoplasm into 2 new cells; follows mitosis

Eukaryotic cell division- genetic material is precisely equally divided between daughter cells in the form of chromosomes

Chromosomes- are so named because of their ability to absorb certain dyes. Chromo= colored and somes= bodies

Chromatin-DNA- protein complex- organized along thin fiber (nucleic acid and protein)

Sister chromatids- two precise copies of each chromosome

Centromere- holds the two sister chromatids together- then in the process of mitosis the sister chromatids are pulled apart and repackaged as complete chromosome sets in two individual nuclei

Control of Cell Division 10/1 10/2

Growth Factors: chemical and physical- missing nutrients and poisons

PDGF (Platelet Derived Growth Factor) triggers cell division of fibroblast cells

Cell Density- crowding of cells inhibits cell division. This is called density dependent inhibitor. When cells reach a certain density the amount of nutrients and growth regulates is insufficient to allow continued growth of cell population

Restriction point(start)- this is a go/no go decision to divide. Happens in Interphase G1 phase, before S(synthesis) stage. If it is a no go situation, the cell enters a no divide G0 stage. If the cell goes or commits to S stage, it is at the point of no return.

MPF- (m phase promoting factor) OK signal. When MPF reaches a significant level of concentration in the G2 cell, prophase begins. MPF is a member of a family of enzymes called protein kingses; it activates other proteins.

(cdc2 & Cyclin) enzymes that transition the phase. Cdc2 is constant. Cyclin varies; it is cyclic in nature.

Cancer: Abnormal Cell Division

Cancer cells don’t respond normally to body’s control mechanisms

1. Divide excessively

2. Invade other tissue

3. Absorb nutrients detained for neighboring cells

4. Migrate to other sites

5. Can kill if unchecked

These cells do not heed the normal “stop” signals. In particular, they ignore density dependent inhibition. They continue to multiply even after contacting each other. They pile up (form tumors).

Benign tumors don’t spread to other areas

Other differences between normal cells & cancer cells- If and when they stop dividing, cancer cells seem to do so at random points rather than at the restriction point G1.

Transformation- conversion of a normal cell to a cancer cell. The body’s immune system which usually kills these insurgent cells is tricked or evaded.

Tumor- a mass of cancer cells in an otherwise normal tissue.

Benign tumor- a tumor where the cells remain at the original site (enlarges, doesn’t move)

Malignant tumor- cells spread to other sites in the body.

Malignant tumors are abnormal in many ways:

1. No control over cell division

2. May have abnormal numbers of chromosomes

3. Metabolism may be deranged

4. Cease to function in any constructive way

5. Lose their attachments to neighboring cells and the extra cellular substratum allowing the cancer cells to spread to other tissues

6. Cancer cells may also separate from the tumor and enter the blood and lymph vessels

7. Can invade other parts of the body, proliferate to form more tumors

Metastasis- the spread of cancer cells beyond their original site

10/6

Meiosis- Produces four haploid (sex) cells with 23 chromosomes each. Goes through m cycle twice.

Tetrad- paired homologues with two chromatids each

Meiosis introduces genetic variability

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