SI Worksheet #5 (chapter 10 and 12)
BY123
Meeting: 6/24/15 @ 1pm in EB 132
1. Compare and Contrast Cell Respiration and Photosynthesis
Compare – Both have an ETC
Have ATP synthesized
Involve electron carriers
Involve multiple memebranes and H+ gradients
In organelles with multiple compartments
Both have mitochondria
ContrastPhoto
Creates and fixes energy (Endergonic)
(Exergonic)
Chloroplast
Makes NADpH
2.
Cell Rep
requires and releases energy
Makes NADH
True or false: Plants are the only organisms that perform photosynthesis.
False. Lots of organisms including different bacteria, protists, and alga perform photosynthesis.
3. Draw out the balanced equation for photosynthesis. What type of a reaction is this?
6 CO2 + 12 H2O + Light energy → C6H12O6 + 6 O2 + 6 H2O
This is an endergonic reaction. It requires light energy to be put into the reaction in order for it
to proceed
4. Photosynthesis is a redox reaction. What is oxidized, and what is reduced?
CO2 is reduced. H2O is oxidized.
5. What are the two parts of photosynthesis? Where do they occur? What happens in each?
The two parts of photosynthesis are the light reactions and the Calvin Cycle. The light reactions
occur in the thylakoid membrane and require light in order to proceed. In the light reactions
H2O splits and O2 is produced, NADPH is produced, and ATP is produced. The Calvin Cycle is
light independent and occurs in the stroma. The Calvin Cycle relies on the ATP and NADPH that
were produced in the light reactions and is the part in which sugar is synthesized.
6. What in chloroplasts absorbs light?
Color pigments absorb light. Chloroplasts have chlorophyll a, chlorophyll b, and accessory
pigments called the carotenoids. These pigments will absorb certain ranges of light in the visible
light spectra. The color that they appear to be is actually the color that they reflect not what
they absorb (chlorophyll actually does not absorb green light). Pigments absorb photons, which
causes electrons to become excited and heat and the photon is released as the electron falls
back down to the ground state.
7. How is ATP synthesized in the light reactions? Describe this part of the process. ATP is
synthesized using photophosphorylation, which is very similar to oxidative phosphorylation in
cellular respiration. The electron transport chain that connects PSII and PSI is embedded in the
thylakoid membrane. It causes the buildup of protons in the thylakoid space, making the
thylakoid space have a higher proton concentration than the stroma, building a proton motive
force. Protons then move through ATP synthase which is also embedded in the thylakoid
membrane, and causes the formation of ATP in the stroma.
8. What is produced by each run of the light reactions? What is produced by each run of the
Calvin cycle?
The linear electron flow light reactions produce 1 ATP and 1 NADH and require 1 water
molecule and sunlight. The cyclic electron flow light reactions produce 1 ATP and require
sunlight. The Calvin cycle requires 3 CO2, 9 ATP, and 6 NADPH and produces 1 G3P.
9. How many pairs of chromosomes does a human have? How many pairs are autosomes? How
many are sex chromosomes? What combination of sex chromosomes constitute male and
female?
23… 22…. 1 ….. XX female…. XY male…
10. Describe the DNA of a bacteria… how does it divide?
Single circular chromosome that does binary fission which is formed by the replication of the
single chromosome, the separation of the chromosome copies, and finally the pinching of the
cytoplasm which results in 2 identical daughter cells.
11. What are the 3 reasons to do mitiosis?
1. Mitosis as a form of reproduction
2. Growth and development
3. Tissue Renewal
12. What are the two types of cells in multicellular organisms? What are the processes by which
these cells are replicated?
The two types of cells in multicellular organisms are somatic (body) cells and gamete (sex) cells.
Somatic cells are created through mitosis. Gametes are created through meiosis.
13. Define sister chromatids. What are they held together by?
Sister chromatids are identical copies of the same genetic material that are held by a
centromere.
14. What are the 3 parts of interphase?
1. G1
2. S – Synthesizes DNA, copies itself.
3. G2 – cant see anything visible, but the cell has already replicated its DNA.
15. What are the 4 main parts of Mitosis? Describe each.
a. Prophase- Start to see chromosomes (centromeres connecting sister chromatids), nuclear
envelope breaks, nucleolus goes away, One centriole moves toward the pole while the other
stays in its original position.
b. Metaphase – Chromosome pairs line up at the equator of the cell and make the metaphase
plate, there are 2 types of spindle fibers- 1. Kinetochore- These connect directly to
chromosomes by way of the kinetochore protein. 2. Non kinetochore proteins – run pole to pole
don’t attach to the chromosomes. 46 chromosomes are lined up at the metaphase plate… these
46 chromosomes contain 92 sister chromatids.
c. Anaphase – The sister chromatids are pulled apart by way of the shortening of the attached
kinetochore proteins. The non-kinetochore proteins lengthen causing the entire cell to
elongate. Important motor molecule of microtubules is DYENIN.
d. Telophase – the nuclear envelope comes back and also the nucleolus… Cytokinesis or the
formation of a cleavage furrow begins which is facilitated by microfilaments and the cell begins
to split into 2 cells each with the original amount of genetic material.
16. Describe the G1, M, G0 and G2 checkpoints.
G1- The checkpoint is crossed when growth factors tell the cell that it needs to begin copying its
DNA
G2 – After all the genetic material has been copied the cell passes G2 which tells the cell
everything is good to go to begin mitosis
M – Tells the cell it is ready to finish mitosis.
G0 – these cells are also called post-mitotic because they do not have the ability to do mitosis.
Muscle and brain cells are in this category. These cells literally come Out of the cell cycle.
17. What do diploid and haploid mean?
Diploid cells are referred to as 2n and have a two of each chromosome (somatic).
Haploid cells are referred to as n and have only one of each chromosome (gametes).
18. What is cancer? How does it develop?
General term for disease caused by the uncontrolled division of cells that spread to other areas
of the body (metastasis). All cancers involve the failure of checkpoints
19. Describe meiosis. Tell how it is similar and how it differs from mitosis. What are the two
different stages called? How many cells are produced?
Before meiosis the DNA is replicated. Meiosis follows the same general steps as mitosis
with slightly different things happening at each step.
Prophase I: homologous chromosomes form a synapsis. Crossing over occurs in which
the chromosomes swap DNA for some sections of the chromosome forming a chiasma.
The rest is like mitosis.
Metaphase I: Homologous pairs line up on the metaphase plate.
Anaphase I: The homologous pairs are pulled apart. Sister chromatid are still intact!
Telophase I: The division is completed and the cells are now haploid.
Meiosis II is like mitosis and works to separate the sister chromatids.
Meiosis I: reductional division
Meiosis II: equatorial division
Four daughter cells are produced.