Limits to cell growth
Cells divide rather than continuing to grow indefinitely due to the fact that the larger the cell
becomes the more demands the cell places on its DNA and the more trouble the cell has
moving enough nutrients and was
Not all cells move through the cell cycle at the same rate.
- most nerve cells and muscle cells do not divide at all once they have developed.
- Other cells like skin, digestive tract, bone marrow cells grow and divide rapidly
Background- it is important to understand where it begins and where it ends. the most
important parts of the cells is its border that separates itself from its surroundings:Cell
The cell membrane regulates what enters and
9-1 Chemical Pathways
Chemical energy and food
One gram of sugar glucose () when burned in the presence of oxygen, releases 3811 calories of
A calorie is the amount of energy needed to raise the temperature of 1 gram of water 1 Celsius
The reactions of photosynthesis
The requirements for photosynthesis were discovered in 1800s but they didn't unravel the
complex reactions that allow the plants to use energy of sunlight to produce carbohydrates until
Inside a chloroplast
8-1 Energy of Life
Energy is the ability to do work.
Without the ability to obtain and use energy life would cease to exist.
Autotrophs and heterotrophs
Energy comes from food
- the energy in most food comes from the Sun
Autotrophs: Plants and some other
At the end of glycolysis about 90% of the chemical energy that was available in glucose is still
- locked in the high-energy electrons of pyruvic acid.
To extract the rest of the energy the cell requires oxygen (one of the world's most powerful
Chromatin and chromosomes
Chromosome is the granular material visible within the nucleus ( usually spread throughout the nucleus and it
consists of DNA bound to protein)
When a cell divides chromatin condenses to form chromosomes that contain gene
During cytokinesis in the female, what divides unequally?
a. the sperm cell
b. the cytoplasm b
c. the ovary
d. None of the above
Mitosis is the process by which ?
a. cytoplasm is divided. WRONG
b. the nucleus is divided into two nu