Flashcards Properties and Diversity of Life

What is the overall purpose of photosynthesis?

Photosynthesis converts solar energy into chemical energy. Plants use CO₂ and H₂O to produce glucose/sugars and O₂.

What are the reactants and products of photosynthesis?

Reactants: CO₂, H₂O, and light energy. Products: glucose/sugars and O₂.

What are the two major stages of photosynthesis?

The two stages are the light reactions and the Calvin cycle (light-independent reactions).

Where do the light reactions occur?

They occur in the thylakoids of the chloroplast.

What is the purpose of the light reactions?

They capture solar energy and convert it into chemical energy that can be used during the Calvin cycle. They also split water and produce O₂.

What is chlorophyll?

Chlorophyll is a pigment that absorbs sunlight and captures the light energy needed for photosynthesis.

How is oxygen produced during photosynthesis?

Water molecules are split during the light reactions, producing oxygen gas.

Where does the oxygen released during photosynthesis come from?

It comes from water (H₂O).

Where does the Calvin cycle occur?

It occurs in the stroma of the chloroplast.

What is the purpose of the Calvin cycle?

It uses CO₂ and chemical energy from the light reactions to build glucose/sugar.

What happens to CO₂ during photosynthesis?

CO₂ enters the plant from the atmosphere and is used during the Calvin cycle. Its carbon becomes incorporated into glucose and can eventually become part of other plant molecules.

How do the light reactions and Calvin cycle work together?

The light reactions capture sunlight and produce chemical energy. The Calvin cycle uses that energy along with CO₂ to build glucose.

Where does photosynthesis occur?

Photosynthesis occurs in the chloroplasts of plant cells.

What are stomata?

Stomata are pores in leaves that allow gases such as CO₂ to move into and out of the leaf.

What are guard cells?

Guard cells surround each stoma and control whether the pore opens or closes.

Why are stomata important for photosynthesis?

They allow CO₂ to enter the leaf so it can be used during the Calvin cycle.

What is one disadvantage of open stomata?

Opening stomata allows gases to move through the leaf, but it can also allow water to escape.

What is the difference between turgid and flaccid guard cells?

Turgid guard cells have gained water and become firm, causing the stoma to open. Flaccid guard cells have lost water and become less firm, causing the stoma to close.

What is the overall purpose of aerobic cellular respiration?

It breaks down glucose to obtain usable energy in the form of ATP.

What does aerobic mean?

It means the process uses oxygen.

What are the three major stages of cellular respiration?

Glycolysis, the Krebs/citric acid cycle, and the electron transport chain/oxidative phosphorylation.

What happens during glycolysis?

Glycolysis is the first stage of cellular respiration and begins breaking down glucose.

What happens during the Krebs/citric acid cycle?

The breakdown of glucose-derived molecules continues during this stage.

What happens during the electron transport chain?

The electron transport chain/oxidative phosphorylation produces a large amount of ATP.

What is oxygen's role in aerobic cellular respiration?

Oxygen is a reactant used during aerobic cellular respiration.

What happens to CO₂ during cellular respiration?

CO₂ is produced as a product of cellular respiration.

How are photosynthesis and cellular respiration connected?

Photosynthesis produces sugars and oxygen that can support cellular respiration. Cellular respiration uses them to obtain ATP and produces CO₂ that can be used during photosynthesis.

What nutrients are discussed in relation to cellular respiration?

Carbohydrates, lipids, and proteins. The lab specifically emphasizes that sugars are broken down during cellular respiration to obtain ATP.

What are the four major types of biologically important molecules?

Carbohydrates, proteins, lipids, and nucleic acids.

What are the building blocks of carbohydrates?

Simple sugars called monosaccharides, such as glucose.

What is an important function of carbohydrates?

They can be broken down during cellular respiration to produce ATP and can also function in storage and cell structure.

What are proteins made of?

Proteins are polymers made from amino acids.

What are some functions of proteins?

Proteins have many cellular functions, including functioning as enzymes and serving structural and other roles.

What are lipids made from?

Fats are formed by joining glycerol and fatty acids.

What are some functions of lipids?

Lipids can store energy and are important components of cell membranes and other cellular structures.

What are nucleic acids made from?

Their building blocks are nucleotides.

What are nucleic acids important for?

They are important for storing and transmitting genetic information.

What does a Chemstrip test for?

Glucose.

What is a positive Chemstrip result?

Brown.

What does iodine test for?

Starch.

What is a positive iodine result?

Dark blue or black.

What does Biuret test for?

Protein.

What is a positive Biuret result?

Violet/purple.

What does Sudan IV test for?

Lipids/fats.

What is a positive Sudan IV result?

Red.

What does a positive biochemical test mean?

It means the molecule being tested for was detected.

What does a negative biochemical test mean?

It means the molecule being tested for was not detected.

Why are controls used in biochemical tests?

Controls provide a comparison so you can determine what a positive or negative reaction should look like.

What does a positive control show?

It shows what a known positive reaction should look like.

What does a negative control show?

It shows what a known negative reaction should look like.

What does lactase break down?

Lactase breaks down the sugar lactose.

What two simple sugars make up lactose?

Glucose and galactose.

How can you test whether lactase successfully broke down lactose?

Use a Chemstrip to test for glucose. If glucose is detected, that supports that lactose was broken down.

Why is glucose important in the lactase experiment?

Glucose is one of the products expected when lactase breaks down lactose, and Chemstrips can detect glucose.

Why was heat-treated lactase used?

Heat can change an enzyme's shape and affect its function. The experiment demonstrates how changing lactase's structure can interfere with its ability to work.

What does the maltose portion of the lactase experiment demonstrate?

It demonstrates enzyme specificity. Lactase is specific for its substrate, lactose, rather than simply working on any sugar.

What are the main ideas demonstrated by the lactase experiment?

Lactase breaks down lactose, glucose can be detected with a Chemstrip, enzymes are specific, and changing an enzyme's structure can affect its function.

If a mystery substance turns brown with a Chemstrip, what does that suggest?

It suggests glucose is present.

If iodine turns dark blue/black, what does that suggest?

It suggests starch is present.

If Biuret turns violet/purple, what does that suggest?

It suggests protein is present.

If Sudan IV produces a red color, what does that suggest?

It suggests lipid/fat is present.

If a question asks where the light reactions happen, what should you think?

Thylakoids.

If a question asks where the Calvin cycle happens, what should you think?

Stroma.

If a question asks where photosynthetic oxygen comes from, what should you think?

Water.

If a question asks what happens to CO₂ during photosynthesis, what should you think?

CO₂ is used in the Calvin cycle to help build sugar.

If a question asks what cellular respiration does with glucose, what should you think?

It breaks glucose down to obtain energy in the form of ATP.

If a question asks what photosynthesis provides for cellular respiration, what should you think?

Glucose/sugar and O₂.

If a question asks what cellular respiration provides that photosynthesis can use, what should you think?

CO₂ and H₂O.

What are the four biochemical tests you should know without hesitation?

Chemstrip -> glucose -> brown

Iodine -> starch -> dark blue/black

Biuret -> protein -> violet/purple

Sudan IV -> lipid -> red

What is the biggest connection between all of these topics?

Photosynthesis captures energy and makes sugars and oxygen; cellular respiration uses nutrients such as sugars to produce ATP; and the biomolecule/testing experiments help you identify and understand the molecules involved in these cellular processes.