|GENBIO.| CELL CYCLE & RESPIRATION

CELL RESPIRATION

• life is at work.

• work needs energy (ATP).

• Photosynthesis generates molecules.

• cellular respiration uses energy to store organic molecules of to make ATP, powers work.
  
  *Three stages*
  
  Stages & locations are
  
  1. GLYCOLYSIS in the cytosol
  
  2. CITRIC ACID CYCLE in the mitochondrial matrix
  
  3. ETC AND CHEMIOSMOSIS in the inner membrane
  

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  GLYCOLYSIS
  
  Breaks glucose into 2 molecules of PYRUVATE
  
  Two major phases
  
  1. ENERGY INVESTMENT
  
  2. ENERGY PAYOFF
  
  Occurs whether or not O2 is present

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  PYRUVATE OXIDATION
  
  In presence of O2,
  
  * Pyruvate enters mitochondria
  
  converted to acetyl CoA
  
  Links glycolysis to the citric acid cycle

CITRIC ACID CYCLE

Completes the breakdown of pyruvate to CO2

Turns 2X, each turn uses a molecule of
Generates, per Acetyl CoA

* 1 ATP

* 3 NADH

* 1 FADH2

NADH, FADH2 relay electrons to ETC

ELECTRON TRANSPORT CHAIN

Occurs on the inner membrane

Composed of a series of protein complexes

Electrons fall to lower state of energy

ultimately passed to O2

* Combine with H ions, forming H2O

CHEMIOSMOSIS

As electrons pass along the ETC, H ions are pumped into the inner membrane space

Creates a gradient called the PROTON MOTIVE FORCE

H ions eventually pass back into the mitochondrial matrix through ATP synthase

(membrane enzyme)

PM Force drives work....ATP production

ENERGY EFFICIENCY

Only 34% of energy stored in glucose is used to make ATP... remainder is lost asheat

CELL CYCLE

INTRODUCTION

Life is based on the production of cells through a process called CELL DIVISION

Significance

1. growth & development

2. tissue repair

3. repoduction

CELL CYCLE

A series of events occurring with a cell, leading to it's growth & ultimate division

Has two phases

1. INTERPHASE

2. MITOTIC (M) PHASE

* mitosis

* cytokinesis

INTERPHASE

A cell spends majority (over 90%) of it's life in this phase

subdivided into three stages

1. G1 phase

2. S phase

3. G2 phase

INTERPHASE - nucleus is intact; DNA molecules replicate themeselves

MITOSIS

Prophase - Nuclear envelope breaks apart; chromatin condenses into chromosomes

Metaphase - Chromosomes line up along the eqautorial plane

Anaphase - shortest one, chromosomes seperate & move toward opposite poles

END RESULT OF MITOSIS:
1. makes 2 same cells
2. each one is a diploid (2n)
3. process accounts for all somatic (body cells)
4. EXCEPT: gametes/sex cells are made by another type of cell division called meiosis

Telophase - nuclear envoleopes reform, chromosomes de-condense back intochromatin network

CYTOKINESIS

cystoplasm divides, separates, daughter cells occurs

Animal cells = cleavage furrow forms; cells “pinched” into daughter cells

Plant cells (- cell plate (wall) froms with b/w daughter

CELL CYCLE REGULATION
Regulated by a cell cycle control system, factors include internal & external signs
1. G1 phase - checks if DNA is damaged, suffiecent cell size & proper enviromental conditions
2. G2 - makes sure that DNA is copied correctly
3.M phase - makes sure chromosomes are aligned & attached to spindle apparatus before anaphase

EXTERNAL FACTORS
* can be physical

Factors are:
1. Ancho.rage depend.ence - cell has to be together to a solid surface to grow and seperate
2. Density depend.ent inhibition - cells STOP dividing when they reach a limit density (crowding)

CANCER
uncontrolled growth. 7 divison of abnormal cells
cells can’t respond to normal cell cycle controls
abnormal mass of cells is a tumor
metastasis - spreads to other locations

* benign - mass is NOT cancer
* malignant - mass is CANCER

CANCER PREDICTION

1. US, cancer will effect
2. 1 in 2 men
3. 1 in 3 women
4. cases will double by 2050