Midterm

Question 1

Each of the items listed below is involved in the energy process utilized by living things. What is the relationship of these items.
a.) NADPH
b.) ATP
c.) Sunlight
d.) Glucose

Answer 1

NADPH and ATP are molecules that store and transfer energy.
Sunlight is the initial source of energy that drives the process.
Glucose is the end product, representing stored chemical energy.

Question 2

What stage of photosynthesis captures light energy and converts it into chemical energy temporally stored in NADPH and ATP?

Answer 2

Light Dependent Reaction

Question 3

What stage of photosynthesis utilizes NADPH, ATP, and CO2 to make glucose?

Answer 3

Light Dependent Reaction

Question 4

What are the products and reactants of light dependent reaction?

Answer 4

Products: Oxygen💨 ATP ⚡️ NADPH ⛽️
Reactants: Water💧ADP NADP+

Question 5

What are the products and reactants of light independent reaction? (Calvin Cycle)

Answer 5

Products: Glucose, NADP+, H2O
Reactants: CO2, ATP, NADPH

Question 6

What is the main purpose of photosynthesis?

Answer 6

The main purpose of photosynthesis is to convert light energy into chemical energy stored in glucose, providing a source of energy for living organisms.

Question 7

The original source of energy most living things is what?

Answer 7

sunlight☀️

Question 8

Considering matter (atoms) and energy, do both need to be recycled, one need to be recycled (which one), or neither be recycled.

Answer 8

Both matter (atoms) and energy need to be recycled in living systems. Matter is recycled through various biogeochemical cycles (e.g., carbon cycle, nitrogen cycle), while energy flows through ecosystems and is not recycled.

Question 9

Describe the molecule that makes up cell membranes (how it arranges itself in the membrane, name, structure, and properties).

Answer 9

The molecule that makes up cell membranes are phospholipids. It arranges itself in a bilayer, with hydrophobic tails facing inward and hydrophilic heads facing outward.

Question 10

Describe the molecule that can be saturated or unsaturated (structure, name, what makes it saturated or unsaturated, polar or nonpolar, number of hydrogen atoms in saturated vs unsaturated, which type is healthier, which type is liquid and which is solid at room temperature?

Answer 10

The molecule that can be saturated or unsaturated are fatty acids:
Saturated fatty acids have single bonds and are solid at room temperature.
Unsaturated fatty acids have double bonds and are liquid at room temperature.
Saturated fatty acids have more hydrogen atoms than unsaturated ones.
Unsaturated fats are generally considered healthier.

Question 11

Types of atoms in carbohydrates, lipids, proteins and how to differentiate one class of biomolecules from another. Which one is not soluble in water?

Answer 11

Types of atoms in biomolecules:
Carbohydrates: Carbon, hydrogen, oxygen
Lipids: Carbon, hydrogen, oxygen (higher ratio of hydrogen to oxygen than in carbohydrates)
Proteins: Carbon, hydrogen, oxygen, nitrogen (and sometimes sulfur)
Nucleic acids: Carbon, hydrogen, oxygen, nitrogen, phosphorus

Carbohydrates are generally soluble in water, while lipids (fats) are not soluble in water.

Question 12

Describe the primary, secondary, tertiary, and quaternary structure of a protein.

Answer 12

Primary Structure: The linear sequence of amino acids in a polypeptide chain.
Secondary Structure: Localized folding patterns, such as alpha helices and beta sheets, formed by hydrogen bonding within the polypeptide chain.
Tertiary Structure: Overall three-dimensional structure of a single polypeptide chain, including interactions between distant amino acids.
Quaternary Structure: Arrangement of multiple polypeptide chains (subunits) in a protein complex.

Question 13

What could happen if you change one amino acid in a particular protein?

Answer 13

If you change one amino acid in a protein, it can alter the protein’s structure and function. This change, known as a mutation, may affect the protein’s ability to perform its specific biological role. The impact can range from negligible to severe, depending on the nature and location of the amino acid substitution

Question 14

Describe the structure and functional groups of amino acids. How do the twenty amino acids differ from each other?

Answer 14

Amino acids have a central carbon atom bonded to a hydrogen atom, an amino group (NH2), a carboxyl group (COOH), and a variable side chain (R group).
The 20 amino acids differ in their side chain (R group), which can be polar, nonpolar, acidic, or basic.

Question 15

What is denaturation? What protein structure is not affected by denaturation?

Answer 15

Denaturation is the alteration of a protein’s three-dimensional structure, causing loss of its biological activity. It is often caused by factors like heat, pH changes, or chemicals. The primary structure is not affected by denaturation.

Question 16

What are the functions of carbohydrates (include functions of monosaccharides and polysaccharides). What are the functions of lipids?

Answer 16

Monosaccharides: Immediate energy source (glucose)

Polysaccharides: Energy storage (starch in plants, glycogen in animals) and **structural support **(cellulose)

The function of lipids: Energy storage, insulation, cushioning of organs, structural components of cell membranes, and signaling molecules.

Question 17

What are the six types of elements that make up 95% of living things?

Answer 17

Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur

Question 18

What determines the behavior of atoms. What is the atomic number of carbon? How many electrons would be in a neutral carbon atom?

Answer 18

The behavior of atoms is determined by their electron configuration. The atomic number of carbon is 6, and a neutral carbon atom has 6 electrons.

Question 19

Know how to determine how many covalent bonds in atom can make? For example, How can you tell that carbon can make four covalent bonds?

Answer 19

Carbon can make four covalent bonds due to its four valence electrons. This allows carbon to form diverse and complex organic molecules.

Question 20

Where does carbon in living things come from? What process incorporates carbon into organic molecules?

Answer 20

Carbon in living things comes from the atmosphere in the form of carbon dioxide (CO2). The process that incorporates carbon into organic molecules is photosynthesis in plants.

Question 21

Give reasons why carbon is the fundamental element of organic molecules, thus living things.

Answer 21

Carbon has a versatile bonding capacity, allowing it to **form stable covalent bonds **with various elements.
Carbon can form long chains and branched structures, contributing to the diversity of organic molecules
Carbon bonds are stable and can form double and triple bonds, adding complexity to molecular structures.
Carbon-based molecules serve as the backbone of biological macromolecules, making carbon the fundamental element of organic molecules and living things.

Question 22

Why do cells (living things) need to synthesize organic molecules (build large molecules)?

Answer 22

Build cellular structures (e.g., cell membranes, organelles).
Store and utilize energy efficiently.
Carry out essential biological functions (e.g., enzymes, hormones).

Question 23

The major bonds of molecules of living things is what type of bond?

Answer 23

Covalent Bonds 🔴—🔴

Question 24

Know what hydrolysis and dehydration are and how many waters are added or removed given the number of monomers.

Answer 24

Hydrolysis: Breaking down polymers into monomers by adding water molecules.

Dehydration (Condensation): Building polymers from monomers by removing water molecules.

In hydrolysis, one water molecule is added for each monomer unit released.
In dehydration, one water molecule is removed for each monomer unit added.

Question 25

Explain why water molecules stick to other water molecules.

Answer 25

Water molecules stick to each other due to **hydrogen bonding**. The **oxygen atom** in water is more **electronegative**, creating a partial negative charge, and the hydrogen atoms carry a partial positive charge. This **polarity** allows **water molecules to form hydrogen bonds, resulting in cohesion**.

Question 26

What biomolecule would make a good water repellent and why?

Answer 26

**Waxes** are **hydrophobic biomolecules** with **long hydrophobic** tails, making them **excellent water repellents**. Their **nonpolar** nature **prevents** them from **interacting with water molecules**, and they** serve as protective coatings** in **plants** and **animals**, **preventing water loss** and providing a **barrier against environmental elements**.

Question 27

List as many reasons as you can for the importance of water to life (living cells).

Answer 27

**Universal solvent** for biochemical reactions. Maintains **temperature stability**. Participates in **metabolic reactions**. Provides **support**. Acts as a **medium for transport**. Facilitates **waste removal**. Supports **life** in **various habitats**.

Question 28

Does water contain lots of energy?

Answer 28

Water itself **does not contain lots of energy.** However, it plays a crucial role in **energy transfer and storage** within living organisms.

Question 29

What happens to living things if they do not obtain a continuous input of energy (think 2nd law of thermodynamics).

Answer 29

If living things do not obtain a continuous input of energy, they **cannot maintain the organization** and complexity required for life. This is in accordance with the second law of thermodynamics, which states that **entropy** (disorder) **tends to increase in a closed system.**

Question 30

What law explains the reason that food chains are 4-5 links long. Explain

Answer 30

The law that explains why food chains are 4-5 links long is the 10% energy rule (**second law of thermodynamics**). Only about **10% of energy** is transferred from one trophic level to the next. As energy is transferred,** some is lost as heat**, limiting the length of food chains to maintain sufficient energy for higher trophic levels.

Question 31

In a chemical reaction when is energy absorbed and when is it released (think breaking bonds of reactants and forming bonds of product). Explain endergonic and exergonic reactions in terms of this information

Answer 31

Energy Absorption: Occurs **during endergonic reactions**, where the **products have higher potential energy** than the **reactants**. **Energy is absorbed to form** complex molecules. Energy Release: Occurs **during exergonic reactions**, where the **products have lower potential energy** than the **reactants**. **Energy is released as bonds** are broken and new bonds are formed.

Question 32

Understand graphs showing exergonic or endergonic reactions and give a major biological process for each.

Answer 32

Exergonic Reaction Graph: The **reactants start at a higher energy level** than the **products**. A major biological process is **cellular respiration**, where **glucose is broken down** to **release energy**. Endergonic Reaction Graph: The **reactants start at a lower energy level** than the **products**. A major biological process is **photosynthesis**, where **light energy is used to build glucose**.

Question 33

Can enzymes be reused, are they specific, are they changed in chemical reactions, do they add energy to the reaction, do they speed up reactions?

Answer 33

Enzymes **can be reused**. They are **specific to particular substrates**. Enzymes are **not changed in chemical reactions**; they **remain unchanged** after catalyzing a reaction. Enzymes **do not add energy to reactions**; they **lower the activation energy** required for reactions. Enzymes **speed up reactions** by providing an alternative pathway with a lower activation energy.

Question 34

How do enzymes speed up chemical reactions without raising the temperature?

Answer 34

Enzymes speed up reactions by **reducing the activation energy** required for the reaction to occur. They do this by **bringing substrates closer together** and providing an environment conducive to the reaction.

Question 35

Know the basics of cell respiration (Reactants, products, what does it extract from food).

Answer 35

Reactants: Glucose and oxygen. Products: Carbon dioxide, water, and ATP Extracts from Food: The process **extracts energy stored** in the **chemical bonds** of glucose through **a series of metabolic reactions**, **ultimately producing ATP** as the main energy currency for cellular activities.

Question 36

If 3 glucose molecules are combined by dehydration synthesis, what would the chemical formula of the resulting molecule?

Answer 36

If 3 glucose molecules are combined by dehydration synthesis, the resulting molecule's chemical formula would be **C18H32O16**.

Question 37

Know reactants and products of light dependent and light independent reactions.

Answer 37

Light-Dependent Reactions: Reactants: Water, ADP, NADP+ Products: Oxygen, ATP, NADPH Light-Independent Reactions (Calvin Cycle): Reactants: CO2, ATP, NADPH Products: Glucose

Question 38

What is the role of pigment molecules in photosynthesis?

Answer 38

Pigment molecules, such as chlorophyll, **absorb light energy** during photosynthesis. This absorbed energy is used to **drive the conversion of carbon dioxide and water into glucose** in the chloroplasts.

Question 39

Where does the oxygen in glucose come from?

Answer 39

The oxygen in glucose comes from **the process of photosynthesis**, where **oxygen is produced as a byproduct** during the light-dependent reactions.

Question 40

What is needed to convert PGA to G3P?

Answer 40

To convert PGA (phosphoglycerate) to G3P (glyceraldehyde-3-phosphate) in the Calvin Cycle of photosynthesis, **energy in the form of ATP** and reducing power from **NADPH is needed.**

Question 41

Why do aquatic organisms have an environment that has less temperature fluctuation than that of land-dwelling organisms (explain the property of water responsible).

Answer 41

Aquatic organisms experience less temperature fluctuation than land-dwelling organisms due to the **high specific heat capacity of water**. Water can absorb and **store a large amount of heat** with only a small change in temperature, **providing a more stable environment for aquatic life**.

Question 42

Recall what happens to BTB when plant or snail or both are placed in BTB under light and dark conditions.

Answer 42

When a plant is placed in BTB under light conditions, the **BTB may turn from yellow** to green or blue, **indicating the presence of oxygen** produced during photosynthesis. When a snail is placed in BTB, it **may produce carbon dioxide**, turning the BTB from **blue to yellow.**

Question 43

Where does the majority of plant mass come from?

Answer 43

Most of the plant mass comes from the **carbon** obtained during photosynthesis. Carbon dioxide from the atmosphere is converted into organic molecules, such as glucose, providing the building blocks for plant growth.

Question 44

What property of water helps it travel up xylem vessels

Answer 44

The property of water that helps it travel up xylem vessels is **capillary action**. Water molecules have **cohesive forces** that allow them to **stick together** and adhesive forces that allow them to **adhere to the walls of the xylem vessels.** This combination of cohesive and adhesive forces **enables water to move upward against gravity** in the plant's vascular system.