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Reporting Category 4: Biological Processes & Systems

B.9B: Compare the reactants and products of photosynthesis and cellular respiration in terms of energy and matter

What are the reactants and products of photosynthesis?

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Photosynthesis is the process by which plants and other autotrophs use light energy to make sugar (glucose) from water and carbon dioxide.

• Reactants: carbon dioxide (CO2) and water (H2O)

• Products: glucose (C6H12O6) and oxygen (O2)

• The chemical equation for the overall reaction is: 6CO2 + 6H2O ( C6H12O6 + 6O2

Photosynthesis is a series of reactions. It involves light-dependent reactions and light-dependent reactions. Light-dependent reactions begin when chlorophyll, a pigment found in plants, absorbs light energy and converts it to chemical energy. Energy is then used in light-independent reactions to produce glucose, and release oxygen as a by-product.

What are the reactants and products of cellular respiration?

Cellular respiration is the process by which cells obtain energy from organic molecules. Both plant and animal cells perform cellular respiration.

• Reactants: glucose (C6H12O6) and oxygen (O2)

• Products: carbon dioxide (CO2), water (H2O), and energy ATP

• The chemical equation for the overall reaction is: C6H12O6 + 6O2 ( 6H2O + 6CO2 + energy (ATP)

Cellular respiration is a series of reactions that break down glucose. The first step is glycolysis in which glucose is broken down into smaller molecules that are transported to the mitochondria. In the mitochondria, reactions of the Kreb’s cycle break down the molecules into carbon dioxide and water. Other products of the Kreb’s cycle then enter a process called electron transport. Electron transport concludes with the combining of hydrogen and oxygen into water.

Kreb’s cycle and electron transport are described as aerobic respiration because they depend on oxygen. If oxygen is not available, cells can perform glycolysis only for a short period of time. This process is called anaerobic respiration or fermentation. Fermentation only produces 2 ATP molecules per molecule of glucose.

How do the reactants and products of photosynthesis and cellular respiration compare?

The products of photosynthesis are the reactants in cellular respiration, and the products of cellular respiration are the reactants of photosynthesis.

Check Your Understanding

1. How are photosynthesis and cellular respiration alike?

a. Both occur only in the presence of light energy from the sun.

b. Both release energy stored in molecules of glucose.

c. Both involve carbon dioxide, water, and oxygen.

d. Both take place in plant and animal cells.

2. Which of the following best describes the difference between the products and reactants of photosynthesis and cellular respiration?

a. The reactants of photosynthesis are made in the cell, while the reactants of cellular respiration come from the environment.

b. The products of photosynthesis are the same as the products of cellular respiration.

c. All the reactants of photosynthesis come from the environment, while some of the reactants of cellular respiration are made by living things.

d. The reactants of photosynthesis are the same as the reactants of cellular respiration.

3. In plant cells, the organelles that conduct photosynthesis are _____________ and the organelles that conduct cellular respiration are the _______________.

a. Chloroplasts and chromoplasts

b. Chromoplasts and leucoplasts

c. Leucoplasts and mitochondria

d. Chloroplasts and mitochondria

4. Which of the following describes the primary energy conversion that occurs when plants produce sugar?

a. Chemical energy is converted to light energy

b. Chemical energy is converted to mechanical energy

c. Light energy is converted to chemical energy

d. Light energy is converted to mechanical energy

5. What is a reactant?

6. What is a product?

7. The reactants and products of photosynthesis are-

8. The reactants and products of cellular respiration are-

B.9C: Identify and investigate the role of enzymes.

Role of an Enzyme:

• Catalyst= a substance that speeds up a chemical reaction

• Enzyme is an organic catalyst in that it speeds up the reactions in living things. Without enzymes, cellular reactions would take too long, and the cell would die before the reaction was complete.

• Enzymes are proteins and are specific to one chemical reaction.

|Examples of Enzymes |

|Enzyme |Catalyzes the… |

|Catalase |Breakdown of hydrogen peroxide to oxygen and water |

|Cellulase |Breakdown of cellulose |

|DNA Polymerase |Production of DNA molecule |

|Kinase |Transfer of phosphate groups from ATP to other molecules |

|Lactase |Breakdown of lactose |

|Lipase |Breakdown of lipids |

|Protease |Breakdown of proteins |

|Sucrase |Breakdown of sucrose |

How Do Enzymes Work?

• “Lock and Key”

o Lock is the enzyme

o Key is the molecule or molecules that bind to the enzyme (substrate)

• Substrates bind to the enzyme at the Active Site and are positioned for a reaction

• Once the reaction is complete, products are released, and the enzyme is free to move on to catalyze another reaction.

Factors Affecting Enzymes

• temperature

• pH

If conditions are not specific, temperature and pH can denature (change the shape of) the protein and become ineffective

B.10A: Describe the interactions that occur among systems that perform the functions of regulation, nutrient absorption, reproduction, and defense from injury or illness in animals

How do systems interact to regulate an animal’s body?

There are several organ systems that work together to maintain an organism’s internal environment, despite changes that occur in its external environment.

The nervous system collects and interprets information from inside and outside the body. It is the master control center for regulation. It also coordinates the responses to this information as needed. Some important structures of the brain include:

• Cerebrum- the largest part of the brain, where you think and reason, stores memories, detects stimuli

• Cerebellum- regulates coordination and helps you keep your balance

• Medulla- controls involuntary processes such as blood pressure and heart rate

• Hypothalamus- controls body temperature (the body’s thermostat)

The nervous system is made up of the brain, spinal cord, and nerves.

The spinal cord extends along the back of the body, and specialized structures called nerves extend from the spinal cord to all parts of the body.

Another system that helps maintain homeostasis is the endocrine system, which is made up of glands that secrete hormones to other parts of the body. Hormones are chemical substances that are made in one organ in the body and travel through the blood to other specific parts of the body where they control activities.

An example of how hormones maintain homeostasis is blood glucose levels. When blood glucose levels rise, insulin is released, which causes glucose to be taken into body cells. If levels of glucose in the blood become too low, a hormone called glucagon causes stored glucose (glycogen) to be released.

Another regulatory system is the respiratory system, which regulates blood levels of oxygen and carbon dioxide. As carbon dioxide levels in the blood rise, the brain sends a message to certain muscles to start breathing faster. As a result, the lungs release the excess carbon dioxide into the environment, and at the same time pick up more oxygen from the environment through tiny sac-like structures called alveoli.

How do systems interact to absorb nutrients?

• All animals are heterotrophs, which means they obtain their energy by eating food.

• To locate and obtain food, animals must use their nervous, muscular, and skeletal systems to some degree.

o sensory clues such as sights and smells alert an animal that food is near

o muscles then pull on bones or skeletal structures to move the animal toward the food

• The nervous system controls the muscles that move food through the digestive system, and then the endocrine system releases hormones to stimulate the pancreas to release enzymes critical in breaking down food.

How do systems interact in reproduction?

• most animals reproduce sexually, which maintains genetic diversity in a population.

• the main job of the reproductive system is to produce haploid gametes, sperm and egg.

• the nervous and endocrine systems send signals to the reproductive system when conditions are right for reproduction.

• when an embryo is developing inside of its mother, many systems interact.

o placenta grows from the tissues of the mother and the embryo

o blood vessels in the placenta carry food and oxygen to the embryo and wastes away from it

o the endocrine system also stimulates milk production in the mother to feed the offspring

How do systems interact to defend the body?

The immune system defends the body from illness. It includes a variety of white blood cells that recognize and attack pathogens, infection-causing agents.

Other systems also defend the body against pathogens.

• Digestive System: acid in the stomach helps kill pathogens that enter the body with food and saliva.

• Integumentary System:

o skin acts as the main barrier between pathogens and internal body tissues.

o mucus membranes line the nose, mouth, and other body cavities, and the mucus they secrete helps trap pathogens and small foreign objects.

The nervous system also protects the body from injury.

• When an animal feels threatened, body systems interact for the sake of protection.

• Adrenaline from the endocrine system and messages from the nervous system help the animal fight or flee its attacker.

• The circulatory, respiratory, and muscular systems all work harder and faster than normal to give the animal oxygen and energy to fight or flee.

Check Your Understanding

1. Which interaction of body systems is an example of homeostasis?

a. The nervous system stimulates muscles to move in the right leg.

b. The endocrine system helps other systems respond to a danger in the environment.

c. When blood sugar is high, hormones stimulate cells to take up sugar from the blood.

d. You remember a happy moment, and you smile.

2. Which process involves the nervous system and endocrine system working together?

a. moving the hand and fingers to scratch an itch

b. jerking the arm away when the hand touches something hot

c. digesting food after it is swallowed

d. swallowing food after it is chewed

3. A student produced this poster to show the interdependence of organ systems. According to the information on the poster, how does the endocrine system affect the circulatory system?

a. The endocrine system increases the

heart rate.

b. The endocrine system metabolizes

liver glycogen.

c. The endocrine system help form plasma

membrane.

d. The endocrine system enlarges arteries.

4. The interaction of which three systems provides the molecules needed for the metabolic activity that takes place at ribosomes?

a. Digestive, endocrine, circulatory

b. Reproductive, endocrine, respiratory

c. Immune, muscular, nervous

d. Integumentary, respiratory, immune

5. The diagram shows one of the processes that occur in vertebrates. According to this information, which two body systems work together during this process?

a. Respiratory and circulatory

b. Immune and endocrine

c. Skeletal and nervous

d. Xylem and phloem

6. As a scab forms on a cut on the back of a hand, the _______________ system and the ____________ system work together.

a. Xylem and phloem

b. Integumentary and circulatory

c. Immune and skeletal

d. Endocrine and reproductive

B.10B: Describe the interactions that occur among systems that perform the functions of transport, reproduction, and response in plants.

How do systems interact in plants to transport water, minerals, and food?

Seed plant cells are organized into tissues, organs, and systems. The three types of tissues found in seed plants are vascular, dermal, and ground. The three main types of organs are roots, stems, and leaves. All are involved in the transport of materials throughout the plant.

Plants use specialized cells to transport water, minerals, and nutrients through the roots, stems, and leaves. Vascular tissue transports materials, such as water, nutrients, and sugars throughout a plant.

• Xylem- transports water and minerals from the plant’s roots, up the stem, and to the leaves

• Phloem- transports nutrients, such as sugars, throughout the plant

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The driving force behind water movement in a plant is transpiration (the loss of water from a leaf). This movement of water from the leaf’s surface pulls other water molecules from the root upward. Water molecules stick to each other (and to the walls of xylem) using hydrogen bonds.

Water escapes from the leaf through pores called stomata. Stomata are surrounded by guard cells, which are plump and form openings when water is plentiful. These openings are important for gas exchange, so that plants can take in carbon dioxide they need for photosynthesis, and remove the oxygen produced in photosynthesis. When too much water has been lost, the guard cells shrivel, which causes the stomata to close. The stomata must balance the need for gas exchange with prevention of excessive water loss.

How do systems in plants interact in reproduction?

Plants use both asexual and sexual reproduction.

Vegetative propagation is a method of asexual reproduction in plants where one plant gives rise to new plants. This can be done by sending out a horizontal stem, either above or below ground. These are called runners and rhizomes.

In sexual reproduction, some plants depend on flowers, which come in a variety of shapes and sizes. The colors, fragrances, and nectars are adaptations to attract pollinators. There are four main parts of a flower:

• The sepals are often green and make up the outermost part of the flower. The sepals protect the flower while it is a bud.

• The stamen is the male reproductive structure of a flower, where pollen is produced. Pollen contains sperm.

• The pistil is the female reproductive structure of a flower.

• The petals are the colorful parts of the flowers, which attract birds and insects.

Pollinators are important because they transfer pollen (with its sperm) to the pistil. The egg is contained at the base of the pistil within an ovule. When the sperm reach the egg, their nuclei fuse in fertilization. After fertilization, the ovule develops into a seed, which protects the tiny, developing plant. The seed is then dispersed by wind, water, or an animal, and when conditions are right (optimal temperature, water, and oxygen), it will germinate (sprout).

How do systems in plants interact to respond to the environment?

Animals respond to all kinds of things. Dogs run after toys, cats chase mice, and you answer questions when you are called on in class. Even though plants can’t run or speak, they still respond to a variety of stimuli, including light, gravity, and even touch. Plant responses are called tropisms. A tropism is the movement of a plant in response to a signal from the environment.

• Positive tropism- movement toward a stimulus

• Negative tropism- movement away from a stimulus

Since plants do not have nervous systems, they rely on hormones to stimulate or inhibit plant growth. A major class of plant hormones is called auxin, which causes plants to grow toward light.

• Phototropism- response to light

• Gravitropism- response to gravity

• Thigmotropism- response to touch

Check Your Understanding

1. In which property does xylem differ from phloem?

a. presence in trees and other tall plants

b. presence in roots, stems, and leaves

c. the direction in which it transports materials

d. tubelike organization

2. The gravitropism of a tree’s trunk explains which of these observations of a tree?

a. The tree develops flowers at the same time every year.

b. The tree grows to a certain maximum height and then stops growing taller.

c. A tree trunk grows slightly wider every year.

d. On a steep hillside, the tree’s trunk is upright and vertical, not tilted.

3. What are differences between xylem and phloem? What do they transport?

4. How do guard cells help regulate water and gas exchange?

5. The diagram shows how hormones produced by a fully developed flower inhibit the development of a bud, temporarily preventing the bud from maturing. Which two systems are interacting in the diagram?

a. Reproductive and response

b. Reproductive and support

c. Support and transport

d. Response and photosynthesis

6. The arrows in the diagram represent the movement of materials.

The movement of these materials is most directly related in the processes of--

a. digestion and recycling

b. Circulation and coordination

c. Respiration and replication

d. Photosynthesis and excretion

7. A plant was set in front of a sunny window for several days. What process caused the plant to grow at an angle?

a. Geotrophism

b. Phototrophism

c. Turgor pressure

d. Photosynthesis

B.10CAnalyze the levels of organization in biological systems and relate the levels to each other and to the whole system.

How are biological systems organized?

How do cells compare to tissues?

• cells are the “building blocks” of multicellular organisms.

• cells with similar structures and functions are organized into tissues.

How do tissues compare to organs, and how do organs compare to organ systems?

• organs, which contain different types of tissues, are body parts that have a particular function.

o Ex: in animals: heart, lungs, brain, skin; in plants: roots, stems, and leaves

• a group of organs that work together to fulfill a function make up an organ system.

o Ex: circulatory system, digestive system, respiratory system, nervous system

How do the levels of organization relate to one another and to the whole system?

• No cell, tissue, or organ can work by itself. Their coordination allows the organism to maintain homeostasis and complete a wide variety of tasks.

Check Your Understanding

1. The femur is a long bone in the upper leg. The femur is classified as an organ because it

a. functions independently of other organs or organ systems

b. is larger than a tissue and smaller than an organ system

c. is made of tissues found nowhere else in the body

d. is composed of several types of tissues that work together

B.11A: Describe the role of internal feedback mechanisms in the maintenance of homeostasis

All cells and organisms must maintain a constant balance in their internal environment in order to stay alive. Homeostasis is the process by which cells maintain a balance. Homeostasis is important because an organism functions properly only within a narrow range of internal chemical and physical conditions. Cells depend on a certain range of temperature and pH, as well as a proper supply of oxygen, energy, and water.

Many organisms use feedback mechanisms to maintain homeostasis. A feedback mechanism is a system of checks and balances in which the end product in a series of steps controls the first step in the series. It involves constant communication by various parts of the body.

Thermoregulation is an example of how homeostasis is maintained through a feedback mechanism. In this case, communication takes place between the brain and the skin. The brain monitors body temperature and sends signals to the sweat glands in the skin. If the temperature is too high, the sweat glands will release water. As sweat evaporates, the temperature drops. Once the temperature is back within a normal range, the brain instructs the sweat glands to stop secreting water. This is an example of negative feedback, because it shuts off the original stimulus to return the body to normal. A negative feedback causes an increase in the product or the result causes a decrease in response.

Some homeostatic mechanisms use a positive feedback system. Positive feedback is the opposite of negative feedback because it causes a further increase in response. One example is the onset of contractions in childbirth. When a contraction occurs, the hormone oxytocin causes a nerve stimulus, which stimulates the hypothalamus to produce more oxytocin, which increases uterine contractions. This results in contractions increasing in amplitude and frequency. Another example is the process of blood clotting. The loop is initiated when injured tissue releases signal chemicals that activate platelets in the blood. An activated platelet releases chemicals to activate more platelets, causing a rapid cascade and the formation of a blood clot.

Check Your Understanding

1. When blood glucose levels increase, the pancreas releases insulin. Insulin causes body cells to take up glucose, and blood glucose levels decrease. In a negative feedback mechanism, what will happen next?

a. The pancreas will release more insulin.

b. The pancreas will stop releasing insulin.

c. Cells will take in more glucose.

d. Cells will take in insulin.

2. The hypothalamus acts like a thermostat for the body because it

a. can be adjusted to maintain a wide range of body temperatures.

b. releases enzymes into the blood that help maintain a constant body temperature.

c. sends messages to muscles and glands that help maintain a constant body temperature.

d. directly senses the air temperature and adjusts body temperature to match it.

3. How do feedback mechanisms affect homeostasis?

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Phototropism

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