Biology Review Ch Review Chapters 5 & 6

Chapter 5 Photosythesis and Cellular Respiration Energy and Living Things:  Energy from sunlight flows through living systems, from autotrophs to heterotrophs  Photosynthesis and cellular respiration form a cycle because one process uses the products of the other  ATP supplies cells with energy needed for metabolism

Photosynthesis  Photosynthesis has three stages. First, energy is captured from sunlight. Second, energy is temporarily stored in ATP and NADPH. Third, organic compounds are made using ATP, NADPH, and carbon dioxide.  Pigments absorb light energy during photosynthesis  Electrons excited by light, travel through the electron transport chains in which ATP and NADPH are produced

Photosynthesis  Through carbon dioxide fixation, by the Calvin Cycle, carbon dioxide in the atmosphere is used to make organic compounds, which store energy.  Photosynthesis is directly affected by environmental factors such as the intensity of light, the concentration of carbon dioxide, and temperature.

Cellular Respiration  Cellular respiration has two stages: First, glucose is broken down to pyruvate during glycolsis, making some ATP. Second, a large amount of ATP is made during aerobic respiration.  When oxygen is not present, NAD+ is recycled during the anaerobic process of fermentation.  The Krebs Cycle is a series of reactions that produce energy storing molecules during aerobic respiration.

Cellular Respiration  During aerobic respiration, large amounts of ATP are made in an electron transport chain.  When oxygen is not present, fermentation follows glycolysis, regenerating NAD+ needed for glycolysis to continue.

Chapter 6 Chromosomes and Cell Reproduction Chromosomes:  Cell division allows organisms to reproduce asexually, grow, replace worn-out or damaged tissues, and form gametes  Bacteria reproduce by binary fission  Before cell division, DNA coils around proteins and the chromosomes condense. At cell division, each chromosome consists of two chromatids attached at the centromere.

Chapter 6 Chromosomes and Cell Reproduction  Each organism has a characteristic number of chromosomes  Human somatic cells are diploid, with 23 pairs of homologous chromosomes.  Human gamates are haploid, with 23 chromosomes.  Sex chromosomes carry information that determines an organism’s sex or gender  Changes in chromosome number or structure can cause abnormal development.  Karotypes are used to examine an individual’s chromosomes.

The Cell Cycle  The life of a eukaryotic cell, known as the cell cycle, includes interphase, mytosis, and cytokinesis.  Interphase consist of three phases Growth DNA synthesis (replication) Preparation for cell division  A cell about to divide enters the mitosis and cytokinesis phases of the cell cycle  The Cell Cycle is carefully controlled; failure of this control can result in cancer

Mitosis and Cykokinesis  During mitosis, spindle fibers drag the chromatids to opposite poles of the cell.  A nuclear envelope forms.  Each resulting nucleus contains a copy of the original cell’s chromosomes.  Cytokinesis in animal cells occurs when a belt of protein threads pinches the cell member in half, splitting the cell into two separate cells.  Cytokinesis in plant cells occurs when vesicles from the Golgi Apparatus fuse to form a plate.