Exam 3 Photosynthesis, Cell division

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What makes fermentation different than cellular respiration?

What makes fermentation different is that it makes very little ATP without the use of oxygen. ATP is produced by glycolysis NAD+ is recycled from NADH as pyruvate is reduced to lactate or alcohol fermentation


How can other biological molecules fuel cellular respiration?

Molecules can be converted into molecules that are part of glycolysis or the citric acid cycle. Acetyl-coA from fats is the same so it can enter the citric acid cycle as well.


How does cellular respiration add to the production of biological molecules?

Because it synthesizes ATP from chemioosmosis, H+ ions synthesizes water during the oxidative phosphorylation stage.


What is the summary equation for photosynthesis?

Co2+H20 > C6H12O6+O2


Where in a plant does photosynthesis occur?

It occurs in the leaf of a plant in the chloroplasts. The light reactions stage occurs in the thylakoids of the chloroplasts, and the Calvin cycle occurs in the stroma.


What reactant generates the O2?



Explain how photosynthesis involves oxidation and reduction. Is this similar to the redox process of cellular respiration?

In photosynthesis, the reduction are carbon dioxide and glucose. The oxidation is water and oxygen. The redox process for cellular respiration is that oxidation is glucose and carbon dioxide. The reduction is water and oxygen. So they are similar, but opposite of each other.


What are the two stages of photosynthesis? What reactants and products are used or generated at each stage?

The first stage of photosynthesis is the light reactions stage. The reactant used in this stage is water, and the product is oxygen. The second stage is the Calvin cycle. The reactant used is carbon dioxide, and the product is glucose.


What stage utilizes light energy?

Light reactions stage


What molecules serve as electron carriers for photosynthesis?

The electrons from photosystem I gets his with light energy and gets captured by an electron carrier NADP+ and is reduced into NADPH.


Explain photosystems I and II. Explain how the ATP is made. Why is ATP made during photosynthesis?

In the light reactions stage, photosystem II starts off with electrons getting hit with light energy, which makes them “excited” then they go through the electron transport chain which pushes H+ from low to high concentration. The pressure helps the H+ go through ATPsynthase enzyme and ATP is made. Then in photosystem I, the electrons get hit with even more light energy, and get captured by an electron carrier NADP+. It gets reduced and is NADPH. You’re now left with oxygen. NADPH and ATP go onto the Calvin cycle so that it can make G3P, the sugar that produces glucose.


Compare how ATP is made in photosynthesis versus cellular respiration.

In cellular respiration, the electron carriers cash out the electrons in the electron transport chain. Then the H+ goes against the concentration and that pressure helps H+ go through chemioosmosis and as the H+ go into ATPsynthase the ADP grabs onto a phosphate and you have ATP. In photosynthesis, light energy is supposed to excite the electrons which help them move from low to high concentration. The pressure there helps the electrons go through ATPsynthase and the same process in cellular respiration occurs.


Explain how the light energy is changed into chemical energy.

Electrons removed from water go to photosystem II to I and then are accepted by NADP+ Then the electron transport chain provides energy for the synthesis of ATP by chemiosmosis.


What is the Calvin cycle? What role does it play in photosynthesis?

The Calvin cycle produces sugar within a chloroplast called G3P. This sugar molecule can be used to make glucose or other organic molecules. Rubisco combines with carbon dioxide and G3P and produces ATP.


What are some adaptation plants that have acquired that change or alter the process of photosynthesis?

In hot climates, the stomata in plants will close to reduce water loss; this can still make sugar by photosynthesis. Some plants also use carbon fixation which saves water during photosynthesis. These are called C4 plants because they first fix carbon dioxide into a four carbon compound. (sugar cane or corn) CAM plants conserve water by opening up their stomata and using carbon dioxide only at night. When the carbon dioxide enters it is fixed into a 4 carbon compound and the carbon dioxide is banked releasing it into the Calvin cycle during the day (cacti and pineapple).


How is photosynthesis related to global warming?

Greenhouse gases are increasing which leads to global warming. The rise of carbon dioxide is because of the burning or carbon-based fossil fuels. This can melt polar ice, change weather patterns, and spread of tropical disease. Photosynthesis can alleviate the increase of carbon dioxide into the atmosphere


What is the difference between asexual and sexual reproduction? What types of cells utilize each form of reproduction?

In asexual reproduction there is only one cell needed. It produces sameness (same cell for next generation). Copy and dividing and growth and repair. Undergoes mitosis. For sexual reproduction two cells are needed, sperm and eggs. It divides the genetic info in ½ so that it can make one whole. Undergoes meiosis.


How do prokaryotic cells reproduce?

They only reproduce asexually using binary fisson. Duplication and separation of chromosomes. It continues to elongate and copies move, and then they split.



The genetic info of the cell. It is made up of DNA and proteins called histomes. It’s a “form” that is unorganized. They duplicate into sister chromatids.



Genetic info and copy. “Same generation.” Once they attach together the genetic material condenses during cell division so it can divide properly. It wraps around itself so that it can be a compact chromosome.



Where the two sister chromatids are joined in the middle.



Where the mitotic spindle comes from. It organizes microtubule arrangements. The spindle attaches to the kinectochore.



This prepares cell division. In humans there are 46 chromosomes, so since its duplicating you are left with 92 chromatids. In this stage, the chromosomes duplicate.



The genetic material starts to condense and the spindle starts to form. In this stage, the nuclear envelope starts to break down.



This stage combines prophase and metaphase. The genetic material condenses even more and finishes condensing, so you are left with no nucleus. The spindle has reached the genetic material and grabs a hold of it. The spindle then connects to the entire sister chromatids in the kinectochore.



This is the phase where the entire sister chromatids align in the center of the cell. The cell is almost ready to split. In this stage, there are still 92 chromatids.



In this stage, the sister chromatids are separated by the mitotic spindle and start to come apart. When they split from their sister chromatids, they become chromosomes. This is when the chromosome # doubles. There are 0 chromatids and 92 chromosomes.



Spindle goes away and the new nucleus is formed. The genetic material starts to unravel and called chromatins again. The nuclear envelope also starts to form.


What is one recognizable property of each of the stages?

Prophase: when the nuclear envelope starts to breakdown.
Metaphase: the sister chromatids align in the middle of the cell.
Anaphase: the sister chromatids are pulled apart by the mitotic spindle.
Telophase: a new nucleus and nuclear envelope starts to form, and the genetic material starts to unravel starting the process all over again.


How does cytokinesis differ for plant cells and animal cells?

In plant cells, the cell plate separates it. Material gets delivered in between one plant cell to make a new wall forming two cells. In an animal cell, the cleavage furrow is what indents the cells surface so that they can pinch off each other.


What are some factors that affect cell division and how is cell division regulated?

Cell division is regulated by check points in the cell. Factors that affect cell division are presence of nutrients, growth factors, presence of other cells that cause density-dependent inhibition, and contact with a solid surface (anchorage dependence) Cells anchor to the dish surface and divide. When cells form a single layer, they stop dividing (density-dependent inhibition) if some cells are scraped away, the remaining cells divide to fill the dish with a single layer and then stop (density dependent)


Understand which cells are haploid and diploid. Which are generated by mitosis and meiosis?

Diploid cells are two sets, one from sperm and one from egg. Then at the end of Meiosis you are left with four haploid cells. In diploid cells (2 sets = 2n), there are 46 chromosomes (1 set has 23) and in haploid cells one set has 23 chromosomes


What are similarities and differences between mitosis and meiosis?

In mitosis: two genetically identical cells are produced with the same chromosome number as the original cell it started with.
In meiosis: four genetically identical cells are produced, with half the chromosome number as the original cell it started with.
Both use cytokinesis that occurs after telophase. Both use spindle fibers to separate the chromatids. They both only occur in eukaryotic cells



In mitosis: two genetically identical cells are produced with the same chromosome number as the original cell it started with.
In meiosis: four genetically identical cells are produced, with half the chromosome number as the original cell it started with.



A group of four chromatids of a homologous pair formed by synapsis.


How is variety generated with meiosis?

In meiosis, two cells are used for cell division, sperm and eggs. And this is variety because genetic info is coming from two different sources.


What are some errors than can occur as a result of meiosis?

When cancer cells are dividing rapidly. An extra copy of chromosome 21 can cause down syndrome, an abnormal chromosome can result in failure of a pair of homologous chromosomes to separate during meiosis I or from the failure of sister chromatids to separate during meiosis II, alterations of chromosome structure can cause birth defects and cancer, abnormal numbers of sex chromosomes do not usually affect survival, and new species can arise from errors in cell division.



getting chemical energy without oxygen (2 ATP)



no oxygen


lactic acid fermentation

only in animals, not plants. instead of making pyruvate it makes lactate


alcohol fermentation

makes ethanol (two carbons each, lose carbon from CO2)


Depending what cell takes in determines:

where it starts


Reactants for photosynthesis

CO2 and H2O


Products for photosynthesis

C6H12O6 and O2


What does photosynthesis require so that the light energy can turn into chemical energy?



What is used in the light reactions stage?

water and light


Without this, the light reactions stage can't happen

H2o, chlorophyll, and light


Where does the calvin cyle take place?

Stroma, fluid inside chloroplasts.


What does the calvin cycle use to make sugar?

carbon dioxide


What stage is ATP being used?

Calvin cycle


What is the electron carrier?



What does glucose need in the calvin cycle??



How does the oxygen leave the cell?




Light energy. The shorter the wavelength the greater the energy


Carbon dioxide molecules are?



Photosystem II

Proten in the membrane. The electrons get hit with light enery and they get excited. Then go through the electron transport chain and pushes H+ from love to high concentration. The pressure pushes the H+ into the ATPsynthase and ATP is made.


Photosystem I

Electrons get hit with even more light and get captured by an electron carrier: NADPH. You're left with O2 and the NADPH and ATP move onto the calvin cycle into the stroma


What is needed in the calvin cyle?



What powers sugar synthesis?

co2, h2o, and nadph


What is the three carbon sugar called?



What is the starting material for the Calvin cycle

fivecarbon sugar named ribulose bisphosphate


What helps the carbon fixation step?

The enzyme rubisco


What does the calvin cycle require that gives off ATP?

three carbon molecules, NADPH and ATP


What other process do plants undergo?

cellular respiration


what is photorespiration?

When no ATP or g3p is made because the oxygen doesnt provide carbon dioxide.


What is a c4 plant?

A plant that cannot do calvin cyle right away because the stomata is closed in light reactions stage. This happens in droughts. Uses most ATP


What is a CAM plant?

Uses most ATP. Extreme daytime heat. Stomata opens at night and then undergoes calvin cycle.


How to prokaryotes reproduce?



Outcome of mitosis

two genetically identical cells with the same chromosome number as the original cell. Copies and divides into two cells.


Outcome of meiosis

four genetically different cells with half the chromosome number of the original call.


What stage do chromosomes duplicate?



Why does chromatin condense?

So that it can be more mobile



two sets. 46 chromosomes 23 from both mom and dad.


Goal of meiosis

start with two sets and end up with one. either a sperm or egg


How many divisions are in mitosis?

One division (sister chromatids)


How many divisions are in meiosis?

Two divisions (one to split up 2n to n and then the splitting of sister chromatids)


What is a tetrad?

four chromosomes that come together. Is formed during prophase in meiosis I


What are similarities between mitosis and meiosis?

They both have genetic info and both start as diploids


What is unique to meiosis?

There are two divisions (duplications) the pair and then the sister chromatids split.


When do the homologous pairs split?

Anaphase I of meiosis


When does diploid change to haploid?



When do the sister chromatids split in meiosis?

Anaphase II


During prometaphase in meiosis, what causes the variety?

when tetrads form because of synapsis


How do chromosomes line up in the center during meiosis?

They are mixed, the do not line up in order. And when the chromosomes are split, it becomes a mixture of mom and dads chromosome in each cell. An example of this is how siblings do or dont look like each other.


What is crossing over?

When genetic info is exchanged between homologous chromosomes.


What is a karyotype?

A picture of chromosomes. This cannot happen in chromatin form , it must be condensed. Scientists stop the cell at metaphase and take/use white blood cells. Then they line them up and put them together. They look to see if they are complete with the right sizes and complete sets of two.


What is non disjunction?

when homologous chromosomes dont have a perfect split, or dont split properly. Same with chromatids. Examples are not being able to seperate or genetic material wont split


Trisomy 31?

three copies of the # 21 chromosome. This is down syndrome. "Got three from a non disfunction"



Male (sperm)



Female (egg)


What are the errors of copying and dividing?

deletion, duplication, and inversion (flipping)


What aligns in the center of the cell in meiosis during metaphase I?

homologous pairs


What aligns in the center of the cell in meiosis during metaphase II?

sister chromatids


In which meiosis phase does synapsis occur?

Meiosis I