Science 9 Module 5 Ecosystem: Life Energy Part 1

Summary

Teacher Josie's video offers an insightful exploration into the ecosystem's energy dynamics, focusing on photosynthesis and respiration. It explains how plants, as primary producers, harness sunlight to convert carbon dioxide and water into glucose and oxygen, a process vital for their growth and sustenance. The video delves into the mechanics of photosynthesis, detailing the light-dependent and light-independent reactions, and their significance in the food chain. It also touches on cellular respiration and metabolism, using key terms like ATP, NADPH, and chlorophyll to enhance understanding. Engaging questions and activities are included to test viewers' comprehension, making it an educational and interactive learning experience.

Takeaways

• 🌿 **Importance of Photosynthesis**: Photosynthesis is crucial for all life as it allows plants to convert light energy into chemical energy, providing sustenance for themselves and other organisms.
• 🔬 **Stages of Photosynthesis**: The process can be divided into two main stages: the light-dependent reactions that occur in the thylakoid membrane and the light-independent reactions or Calvin cycle that take place in the stroma.
• 🌱 **Plants as Producers**: Plants, along with certain algae and prokaryotes, are primary producers that capture sunlight and produce their own food, serving as the base of the food chain.
• 🍃 **Leaves in Photosynthesis**: Leaves are the primary organs for photosynthesis, with key parts like the epidermis, mesophyll, and stomata playing essential roles in the process.
• 🌞 **Light Energy Role**: Light energy is absorbed by chlorophyll and used to power the reactions of photosynthesis, highlighting the importance of sunlight for life on Earth.
• 💧 **Water's Role in Photosynthesis**: Water is a key reactant in photosynthesis, not only providing hydrogen for glucose production but also releasing oxygen as a byproduct.
• 🌱 **Chlorophyll's Function**: Chlorophyll within the chloroplasts is responsible for capturing light energy and initiating the light-dependent reactions of photosynthesis.
• 🔋 **Energy Storage in ATP and NADPH**: ATP and NADPH, produced during the light-dependent reactions, store energy that is later used in the Calvin cycle to fix carbon dioxide.
• 🔄 **Calvin Cycle's Efficiency**: The Calvin cycle operates through a series of reactions, requiring six turns to produce one glucose molecule, demonstrating the complexity of energy conversion in plants.
• 🌳 **Plants as Food Providers**: Plants are often referred to as 'great food providers' because they manufacture energy-rich glucose through photosynthesis, which is essential for the survival of animals and humans.

Q & A

What is the primary focus of the video by Teacher Josie?

The video focuses on the concept of ecosystem life energy, explaining the basic features and the importance of photosynthesis and respiration in sustaining life.

Why are plants considered great food providers?

Plants are considered great food providers because they produce their own food through photosynthesis and serve as the primary source of food for all consumers, including animals and humans.

What are the major stages in photosynthesis?

Photosynthesis can be divided into two major stages: the light-dependent reaction, which occurs in the thylakoid membrane and requires light, and the light-independent reaction or carbon cycle, which takes place in the stroma of the chloroplast.

What is the role of chlorophyll in photosynthesis?

Chlorophyll is the green pigment in plants that absorbs light energy from the sun, which is then used to power the chemical reactions of photosynthesis.

What are the functions of the different parts of a leaf in relation to photosynthesis?

The upper and lower epidermis help retain water and regulate gas exchange through stomata. The mesophyll layer contains chloroplasts with chlorophyll for light absorption. The vascular bundles transport nutrients, and the stroma within chloroplasts is where the chemical reactions of photosynthesis occur.

How does the Calvin cycle contribute to the production of glucose in plants?

The Calvin cycle uses the ATP and NADPH produced during the light-dependent reactions to fix carbon dioxide and produce glyceraldehyde 3-phosphate, which can be used to make glucose and other carbohydrates.

What is the significance of the electron transport chain in the light-dependent reaction of photosynthesis?

The electron transport chain in the light-dependent reaction is significant as it facilitates the transfer of energized electrons, which leads to the production of ATP and NADPH, essential for the synthesis of glucose during the Calvin cycle.

What is the role of ATP in the process of photosynthesis?

ATP, or adenosine triphosphate, is a high-energy molecule that stores energy produced during the light-dependent reactions of photosynthesis and is later used in the Calvin cycle to power the synthesis of glucose.

How does the process of photosynthesis help in the production of oxygen?

During the light-dependent reactions of photosynthesis, water molecules are split, releasing oxygen gas into the atmosphere as a byproduct.

What is the significance of the abbreviations NAD, ATP, and FAD mentioned in the script?

NAD stands for nicotinamide adenine dinucleotide, ATP for adenosine triphosphate, and FAD for flavin adenine dinucleotide. These are important molecules involved in energy transfer and electron transport during cellular respiration and photosynthesis.

Outlines

00:00

🌿 Introduction to Ecosystem and Energy

Teacher Josie introduces the concept of ecosystems and energy flow within them. The video is designed to educate about how organisms obtain energy from food and produce energy through processes like photosynthesis and respiration. Key questions are posed to ponder upon after the video, such as why plants are called great food providers and the parts of plants involved in photosynthesis. The script also introduces the concept of metabolism and the role of chlorophyll in plants. It explains the importance of producers like plants, algae, and certain protists that capture light energy from the sun and are considered autotrophs, producing their own food.

05:02

🌱 Understanding Photosynthesis

This section delves into the process of photosynthesis, explaining how plants use light energy from the sun and carbon dioxide to produce glucose and oxygen. The script describes the parts of a leaf involved in photosynthesis, including the epidermis, mesophyll, and chloroplasts. It details the light-dependent reactions occurring in the thylakoid membrane and the role of chlorophyll in absorbing light energy. The process of converting light energy into chemical energy through the electron transport chain and the production of ATP and NADPH are also explained. The script further discusses the light-independent reactions or the Calvin cycle, which uses ATP and NADPH to fix carbon dioxide and produce carbohydrates.

10:04

🔬 The Calvin Cycle and Its Significance

The third paragraph focuses on the Calvin cycle, the light-independent reactions of photosynthesis that occur in the stroma of the chloroplast. It explains the three phases of the cycle: carbon fixation, carbon dioxide reduction, and regeneration of RuBP. The Calvin cycle uses the ATP and NADPH produced during the light-dependent reactions to reduce carbon dioxide into glyceraldehyde 3-phosphate, which can then be used to make glucose, fatty acids, or glycerol. The script also outlines the chemical equation of the Calvin cycle and how multiple turns of the cycle are needed to produce one molecule of glucose.

15:05

📝 Summary and Activity on Photosynthesis

The final paragraph summarizes the process and products of the Calvin cycle and provides an activity to reinforce understanding. It includes a quiz with statements related to light-dependent and light-independent reactions, asking viewers to identify which processes are associated with each. The script ends with a call to action for viewers to like, share, subscribe, and turn on notifications for more educational content, thanking them for watching.

Keywords

💡Ecosystem

An ecosystem refers to a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. In the video, the concept of an ecosystem is foundational as it sets the stage for understanding how energy flows through different organisms and how they are interconnected. The script discusses how plants, as primary producers, capture energy from the sun and convert it into a form that can be used by other organisms, highlighting the ecosystem's interdependence.

💡Photosynthesis

Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll pigments. It is central to the video's theme as it explains how plants produce their own food and oxygen, which are essential for life on Earth. The script details the stages of photosynthesis, including light-dependent reactions and the Calvin cycle, and how they occur within the chloroplasts of plant cells.

💡Respiration

Respiration is the process by which living cells convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. While the video primarily focuses on photosynthesis, respiration is mentioned as the complementary process where organisms, including plants, break down glucose to release energy. This is crucial for understanding the balance of energy in ecosystems and the interconnectedness of life processes.

💡Chlorophyll

Chlorophyll is the green pigment present in the chloroplasts of plants that plays a crucial role in photosynthesis by capturing light energy. The video script explains that chlorophyll's ability to absorb light is what allows photosynthesis to occur, making it a key component in the process of energy conversion within plants.

💡Autotrophs

Autotrophs are organisms that can produce their own food from inorganic substances, typically using light or chemical energy. In the context of the video, plants are described as autotrophs because they can synthesize their food through photosynthesis, making them the primary producers in an ecosystem and the basis of the food chain.

💡Metabolism

Metabolism encompasses the set of life-sustaining chemical reactions in organisms. The script introduces metabolism as the total chemical processes occurring within a living system, which includes both anabolic (energy-storing) and catabolic (energy-releasing) reactions. It is essential for understanding how organisms, including plants, maintain their life processes.

💡ATP (Adenosine Triphosphate)

ATP is the primary molecule for storing and transferring energy within cells. The video script explains how ATP is produced during the light-dependent reactions of photosynthesis and is then used as an energy source during the Calvin cycle. ATP is central to the video's discussion of energy production and utilization in living organisms.

💡NADPH

NADPH, or nicotinamide adenine dinucleotide phosphate, is a molecule that carries high-energy electrons and hydrogen ions. In the video, NADPH is highlighted as a product of the light-dependent reactions of photosynthesis, which are then used in the Calvin cycle to reduce carbon dioxide, illustrating its role in energy transfer and utilization.

💡Calvin Cycle

The Calvin cycle is a series of biochemical reactions that take place in the chloroplasts during photosynthesis, where carbon dioxide is fixed into an organic molecule. The video script describes the Calvin cycle as the light-independent reactions of photosynthesis, where ATP and NADPH produced in the light-dependent reactions are used to fix carbon dioxide and produce glucose.

💡Stomata

Stomata are the tiny pores found on the surface of leaves that facilitate gas exchange. The video script mentions stomata as the entry points for carbon dioxide and the exit points for oxygen during photosynthesis, emphasizing their importance in the process of gas exchange in plants.

💡Chloroplast

Chloroplasts are the organelles in plant cells that conduct photosynthesis. The video script describes the structure of chloroplasts, including the thylakoid membranes where light-dependent reactions occur and the stroma where the Calvin cycle takes place, highlighting their central role in the energy production of plants.

Highlights

Introduction to the topic of ecosystem life energy and the importance of photosynthesis and respiration.

Key learning competency: Understanding the features and significance of photosynthesis and respiration.

Organisms need energy to sustain life, and this video focuses on how they obtain and produce it.

Plants are called 'great food providers' because they produce their own food through photosynthesis.

Photosynthesis occurs mainly in the leaves, with key parts like the epidermis, mesophyll, and stomata involved.

Chloroplasts in plant cells contain chlorophyll, which captures energy from sunlight.

Photosynthesis can be divided into two stages: the light-dependent reactions and the Calvin cycle.

Light-dependent reactions occur in the thylakoid membrane, where light energy is converted into chemical energy.

The Calvin cycle (light-independent reactions) occurs in the stroma and is responsible for producing glucose.

The chloroplast contains a double membrane, stroma, and thylakoids that are essential for photosynthesis.

Key molecules in the photosynthesis process include ATP, NADPH, and glucose.

Photosystem I and Photosystem II play a major role in the light-dependent reactions.

The Calvin cycle requires ATP and NADPH from the light-dependent reactions to produce G3P, a precursor to glucose.

The equation for photosynthesis: carbon dioxide + water + sunlight → glucose + oxygen.

Photosynthesis helps produce essential molecules like glucose, starch, and cellulose for plant growth and energy.

Transcripts

[Music]

hello everyone welcome to my channel

this is teacher josie that will give you

an idea about ecosystem life energy

the video focuses on achieving this

learning competency

different shade basic features and

importance of photosynthesis and

respiration

in this video you will learn that all

organisms need the energy to sustain

life you will focus on how the organisms

obtain energy from the food and how they

produce energy

here are some key questions for you to

ponder after finishing this video

why are plants called great food

providers

what are the parts of the plants

involved in photosynthesis

what are the major stages in

photosynthesis

let's recall your understanding of the

concepts of photosynthesis and cellular

respiration identify the word based on

the given description

the total chemical processes taking

place within the living system what do

you think is the answer

the answer is metabolism

the green coloring matter of plants

that is chlorophyll

let us first familiarize the different

abbreviation that we are going to

encounter in this study

nad

nicotinamide adenine binocular

biphosphate

nad means

nicotinamide adenine dioxide

atp means adenosine

triphosphate

bgal

phosphoglyceraldehyde

fad

1189 the nucleotide

adp means adenosine diphosphate

the main producers like plants

algae

certain protists and some prokaryotes

capture light energy from the sun for

their needs and to provide energy for

almost all life forms

these producers are considered as

self-feeders or autotrophs because they

produce their own food and sustain

themselves without consuming other

organisms in order to survive

if we look at the hierarchy of food

chain we can see that plants are in the

bottom parts which are considered as

primary source of food for all consumers

like animals including humans

if plants manufacture energy for animals

to use they should have a way to

recharge their nutrients

what is photosynthesis

photosynthesis is the process by which

plants use light energy from the sun and

carbon dioxide to produce glucose the

sugar molecules and oxygen that they use

for growth and nourishment

primarily photosynthesis takes place in

the leaves which are the main organs for

photosynthesis

the typical parts of the leaves include

the upper and lower epidermis

palisade nesophil

mesophyll spongy layer

vascular bundles

and stomata

the upper epidermis the outermost layer

which secretes a waxy substance called

cuticle

this cuticle helps retain water inside

the leaf cells

at the lower epidermis you will see some

openings

each opening is called stoma or stomata

this is where carbon dioxide enters

oxygen passes out

around the stoma is a pair of bin shaped

cells called guard cells

the guard cell is an epidermal cell

with chloroplast that regulates the

opening and flossing of the stomach

between the upper and lower epidermis

you can see layers of cells this is

called mesophyll layer which is composed

of polycyte

cells that are arranged like columns and

spongy cells which are loosely arranged

cells

these cells of organelles known as

chloroplasts that contains green

pigments which trap energy from the sun

the chloroplast is enclosed by a double

membrane in the outer membrane

and an inner membrane

between these membranes is a space

called stroma which is the liquid part

of the chloroplast

embedded in the stroma is a complex

network of stacked socks

each stack is called a granule

or

grana

each of those flattened sacks is called

this

thylakoids that contains green colored

pigments called chlorophylls that absorb

light

the equation used to explain

photosynthesis is as follows

carbon

dioxide and water

with sunlight produces

glucose and

oxygen

photosynthesis involves many steps but

it can be divided into two stages

one the light dependent reaction

and the second is carbon cycle

the light dependent reaction stage

occurs in the thylakoid membrane and

requires a continuous supply of light

during this reaction light energy is

absorbed by the chlorophyll and

converted into chemical energy

in order to plants to grow they need

carbon dioxide

water and energy

the chemical process by which plants use

these resources to manufacture glucose

is called photosynthesis

plants appear green because they reflect

yellow and green wavelengths of light

red and blue wavelengths of light are

absorbed by these pigments and provide

the energy that is used for

photosynthesis

the chemical reactions of photosynthesis

occur within plant cells known as

chloroplast

the light dependent reaction occur in

the thylakoid for conversion of light

energy to chemical energy

is initiated the reactions that

synthesize glucose the carbon cycle pour

in straw

the light dependent reaction stage

occurs in the thylakoid membrane and

requires a continuous supply of light

the chlorophyll is composed of two units

of light absorbing molecule namely the

photosystem 2 or ps2 and photosystem 1

ps1

the light dependent reaction begins when

ps2 receives light energy

the light energy is transferred to

chlorophyll reaction center causing

electrons in the reaction center to

become energized

the energized electrons escape ps2 and

moved an electron acceptor molecule

located in the electron transport chain

to replace the lost electrons in ps2

water is split releasing oxygen

two hydrogen ions and two electrons

the excited electrons

continue to move from photosystem 2 to

photosystem 1 through the electron

transport chain

a protein in the electron transport

chain pumps hydrogen ions from the

stroma into the thylakoid space

as electrons move between those

photosystems they lose energy

photosystem 1 absorb light and

re-energize the electron

the chemical called nadp

accepts the electron and hydrogen and

becomes

nadph

which is high energy molecule

as the hydrogen ions continue to build

up inside the thylakoid

atp synthase allows the hydrogen ions to

travel from the thylakoid to the stroma

by the fusion and captures the energy of

their movement by spinning and stores

that energy in atp

an enzyme found in the thylakoid

membrane uses energy of electrons from

both ps2 and ps1 to create more atp and

to stop the production of nadph

it is important to maintain the right

proportion of

nadph and atp which will be used in the

next phase of photosynthesis

in short

chlorophyll in photosystem 2

absorbs light and energizes an electron

a carrier molecule transports the

electron out and down the electron

transport chain a water molecule is

split

releasing a new electron into the system

and oxygen into the atmosphere

the chlorophyll in photosystem 1 absorbs

light energizing an electron a carrier

removes the electron and the electron

from ps2 replaces it the electron is

accepted by nadp

at the end of the transport chain the

gradient pushes ions through atp

synthase

driving atp synthesis

nadph

and atp go onto the calvin cycle

the second stage of photosynthesis is

the light independent reaction are

carbon cycle which occurs in this trauma

of the chloroplast

this series of complex reactions can be

divided into three phases

carbon fixation carbon dioxide reduction

and regeneration of rubp

the atp and nadph

formed during the light dependent

reactions are used in the stroma to fuel

the carbon cycle reactions

the calvin cycle consists of a series of

reactions that reduce carbon dioxide to

produce the carbohydrate

glyceraldehyde 3-phosphate

the cycle consists of three steps

the first of which is carbon fixation

in this step carbon dioxide is attached

to riboulus 1

5-by-phosphate resulting in a 6-carbon

molecule that splits into 2-3 carbon

molecules

the second step is a sequence of

reactions using electrons from nadph

and some of the atp to reduce carbon

dioxide

in the final step riboluse 1

5-biphosphate is regenerated

for every 3 turns of the cycle

5 molecules of glyceraldehyde

3-phosphate are used to reform 3

molecules of ribolus1 5-biphosphate

the remaining glyceraldehyde 3-phosphate

is then used to make glucose fatty acids

or glycerol

it takes two molecules of glyceraldehyde

3-phosphate

to make one molecule of glucose

phosphate

thus the calvin cycle has to run six

times to produce one molecule of glucose

these molecules can remove their

phosphate and add fructose to form

sucrose

the molecule plants used to transport

carbohydrates throughout their system

glucose phosphate is also the starting

molecule for the synthesis of starch and

cellulose

to sum the process and the products of

calvin cycle the overall chemical

equation of the face is the following

three carbon dioxide

plus

six

nadph plus

five water

plus

nine atp the product is

g3p plus

two hydrogen ions

plus

six nadp plus nine adp plus eight pi

pi stands for inorganic phosphate

six runs of the cycle are needed in

order to come up with one glucose

molecule as mentioned earlier the

surplus g3p which is produced by the

reactions could be used to form other

carbohydrates depending on the

necessities of the plants

did you understand

let's have an activity lights off

lightspot

right

on if the process pertains to light

dependent reaction and writes off if the

process pertains to light and dependent

reaction

number one

it is also known as the dark reaction of

photosynthesis

the answer is

off

2

primary acceptor of carbon is

photosystem 1 and photosystem 2.

the answer is on

sides of the process is in this trauma

the answer is

off

number four

photo recess of water does not pour

the answer is

of

number five

process type is both cyclic and

non-cyclic process

answer is

on

number six

it is a release of oxygen that gives off

aldehydes and hydrogen

upon dehydrogenation

the answer is

on

number seven

it is a process that converts solar

energy into chemical energy

the answer is on

number eight

it is a light dependent process

the answer is

one

nine

process type is cyclic only the answer

is off

number 10

primary acceptor of carbon is rubisco by

phosphate

the answer is off

do you have the same answer

good job

let's check your understanding

which best describes light independent

reactions

a they create energy rich atv and

nadph

b

they are the first phase of

photosynthesis

c they use carbon dioxide to make

proteins

d

they utilize the energy stored in atp

and nadph

comment below if you know the answer

that's all for today please don't forget

to like share subscribe and hit the

notification bell for more videos thank

you for watching bye

[Music]

thanks for watching