S9Q1W7: Photosynthesis & Cellular Respiration (Part 1)

Summary

This educational video script covers the critical biological processes of photosynthesis and cellular respiration, highlighting their importance to life on Earth. It explains how plants produce oxygen and glucose through photosynthesis, utilizing sunlight, carbon dioxide, and water. The script also delves into the structure of chloroplasts and the two stages of photosynthesis: light-dependent reactions and the Calvin cycle. It emphasizes the role of plants in ecosystems, providing food, resources, habitats, and maintaining the atmosphere, concluding with a quiz to test understanding.

Takeaways

• 🌿 **Importance of Plants**: Plants are crucial for life on Earth as they serve as a source of food, provide resources, habitats, and play a role in biogeochemical cycles.
• 🌳 **Photosynthesis**: Plants produce oxygen and glucose through photosynthesis, a process that requires sunlight, carbon dioxide, and water.
• 🔬 **Chloroplasts**: Chloroplasts are the organelles in plant cells where photosynthesis occurs, containing chlorophyll for light absorption.
• 🌞 **Light Dependent Reactions**: These reactions occur in the thylakoids of chloroplasts and require sunlight to oxidize water into oxygen and produce ATP and NADPH.
• 🌱 **Calvin Cycle (Light Independent Reactions)**: This cycle takes place in the stroma of chloroplasts, converting carbon dioxide into glucose without the need for light.
• 🌈 **Visible Light**: Photosynthesis utilizes the visible light spectrum, which is absorbed by chlorophyll to power the process.
• 🌎 **Ecosystem Services**: Plants contribute to the Earth's atmosphere by maintaining oxygen levels and reducing carbon dioxide, thus combating global warming.
• 🌐 **Biogeochemical Cycles**: Plants are involved in biogeochemical cycles like transpiration, which moves water from the soil to the atmosphere.
• 🔋 **ATP Production**: ATP, the energy currency of cells, is produced during photosynthesis, particularly in the light-dependent reactions.
• 🌿 **Plants and Human Life**: Beyond aesthetics, plants provide essential resources such as food, shelter, clothing, and economic benefits like medicine and fibers.
• 📚 **Educational Activity**: The script mentions an advocacy board activity for students, encouraging them to propose projects to prevent human extinction.

Q & A

What is the role of plants in the ecosystem?

Plants play a crucial role in the ecosystem by providing food for almost all organisms, offering resources for humans with aesthetic and economic benefits, providing habitats for different organisms, participating in biogeochemical cycles like transpiration, and maintaining the earth's atmosphere through photosynthesis.

How does photosynthesis contribute to the atmosphere?

Photosynthesis contributes to the atmosphere by producing oxygen, which is essential for cellular respiration, and by removing carbon dioxide, which reduces the greenhouse effect and global warming.

What are the two major biological reactions used by almost all organisms?

The two major biological reactions used by almost all organisms are photosynthesis and cellular respiration.

What is the significance of the color green in leaves?

The color green in leaves is significant because it reflects the green wavelength of light, which is absorbed by the leaves and powers photosynthesis.

What are the reactants and products of photosynthesis?

The reactants of photosynthesis are carbon dioxide and water, while the products are glucose and oxygen.

What is the role of chlorophyll in photosynthesis?

Chlorophyll is the green pigment in plants that is responsible for absorbing light energy, which is essential for the process of photosynthesis.

What are the two stages of photosynthesis?

The two stages of photosynthesis are the light-dependent reactions, which occur in the thylakoids, and the light-independent reactions or Calvin cycle, which occur in the stroma of the chloroplast.

What is the function of the chloroplast in a plant cell?

The chloroplast is an organelle in plant cells that carries out photosynthesis, converting light energy into chemical energy stored in glucose.

What is the role of ATP in the light-dependent reactions of photosynthesis?

In the light-dependent reactions of photosynthesis, ATP is produced using the energy transferred by light and is generated through chemiosmosis with the help of an enzyme called ATP synthase.

How does the Calvin cycle utilize ATP and NADPH?

The Calvin cycle utilizes ATP and NADPH to fix carbon dioxide into glucose. ATP provides the energy, and NADPH provides the electrons needed for the reduction of carbon dioxide.

What is the difference between light-dependent and light-independent reactions in photosynthesis?

Light-dependent reactions require sunlight and occur in the thylakoids, producing oxygen, ATP, and NADPH. Light-independent reactions, or the Calvin cycle, can proceed without light and occur in the stroma, using ATP and NADPH to produce glucose.

Outlines

00:00

🌿 The Importance of Biodiversity and Photosynthesis

This paragraph discusses the concepts of species extinction and the role of environmental changes. It highlights the impact of human activity on the accelerated rate of species extinction and the importance of all species in the ecosystem through the food web. The paragraph also introduces the topic of two vital biological processes, photosynthesis and cellular respiration, emphasizing the crucial role of plants in the life cycle of all living organisms. Plants are highlighted as sources of food, resources for humans with aesthetic and economic benefits, habitats for various organisms, and as key players in biogeochemical cycles and maintaining the earth's atmosphere.

05:00

🌞 Understanding Photosynthesis

This section delves into the process of photosynthesis, explaining how plants convert solar energy into glucose. It describes the role of visible light in photosynthesis and how different colors of light are absorbed or reflected by objects, using shirts of different colors as examples. The paragraph outlines the two major steps of photosynthesis: the light-dependent reactions and the light-independent reactions (Calvin cycle). It introduces the chloroplast as the organelle where photosynthesis occurs, describing its components such as thylakoids, granum, lumen, stroma, inner and outer membranes, and the inter-membrane space. The light-dependent reactions are detailed, explaining how water is oxidized into oxygen, and how ATP and NADPH are produced.

10:03

🍃 The Calvin Cycle and ATP's Role

This paragraph focuses on the light-independent reactions of photosynthesis, also known as the Calvin cycle. It explains how the Calvin cycle uses ATP and NADPH to reduce carbon dioxide into glucose. The paragraph clarifies that while the Calvin cycle does not require light, it relies on the products of the light-dependent reactions. The similarities and differences between the light-dependent and light-independent reactions are highlighted, noting that both processes occur within the chloroplast but at different locations and under different energy requirements.

15:04

📝 Quiz on Photosynthesis

The final paragraph presents a quiz to test the understanding of photosynthesis. It includes five questions that cover the products of photosynthesis, what absorbs light energy, the location of photosynthesis within a plant cell, misconceptions about the Calvin cycle, and the standard formula of photosynthesis. The answers to the quiz are provided, reinforcing the key concepts discussed in the previous paragraphs.

Keywords

💡Extinction

Extinction refers to the state of a species or group of species that no longer exists or is not found in the natural environment. In the video, extinction is discussed in the context of the failure of populations to adapt to environmental changes, with a focus on how human activity has accelerated this process. The script mentions extinct species that once lived in the country, emphasizing the importance of understanding extinction to protect current ecosystems.

💡Ecosystem

An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. The video highlights the vital role that all species play within ecosystems, particularly through the food web. It underscores the interconnectedness of species and how the loss of one can impact the entire system.

💡Photosynthesis

Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll pigments. The video explains photosynthesis as a critical biological reaction that plants use to convert carbon dioxide and water into glucose and oxygen, which are essential for life on Earth. It is highlighted as a process that maintains the Earth's atmosphere and provides oxygen for aerobic organisms.

💡Cellular Respiration

Cellular respiration is the process by which cells break down nutrients to produce energy. Although not directly explained in the script, cellular respiration is mentioned as a counterpart to photosynthesis, as it uses oxygen and glucose to produce energy, carbon dioxide, and water, thus completing the cycle started by photosynthesis.

💡Chloroplast

A chloroplast is an organelle found in plant cells and some algae, responsible for photosynthesis. The script describes chloroplasts as containing thylakoids with chlorophyll, the green pigment that absorbs light energy. Chloroplasts are central to the video's discussion of how plants produce oxygen and glucose.

💡Thylakoid

Thylakoids are membrane-bound compartments within chloroplasts where the light-dependent reactions of photosynthesis take place. The video mentions thylakoids as the site where water is oxidized to produce oxygen and where ATP is generated using light energy.

💡Granum

A granum is a stack of thylakoid membranes found within chloroplasts. The script uses the term granum to describe the structure where chlorophyll is located and where light reactions occur, emphasizing the importance of this structure in the process of photosynthesis.

💡Stroma

The stroma is the fluid-filled space inside chloroplasts where the light-independent reactions, or Calvin cycle, of photosynthesis occur. The video explains that this is where carbon dioxide is reduced into glucose, independent of light energy.

💡ATP (Adenosine Triphosphate)

ATP is the primary energy currency of cells, used to power various cellular processes. In the context of the video, ATP is produced during the light-dependent reactions of photosynthesis and is used to power the Calvin cycle. The script describes ATP as being produced by chemiosmosis and used to convert carbon dioxide into glucose.

💡NADPH

NADPH, or reduced nicotinamide adenine dinucleotide phosphate, is a molecule that carries electrons and hydrogen ions. The video explains that NADPH is produced during the light-dependent reactions of photosynthesis and is used in the Calvin cycle to reduce carbon dioxide into glucose, illustrating the critical role it plays in the energy transfer process.

💡Calvin Cycle

The Calvin cycle is the light-independent reaction phase of photosynthesis that takes place in the stroma of chloroplasts. The script describes the Calvin cycle as the process where carbon dioxide is fixed and reduced into glucose using the energy from ATP and the electrons from NADPH.

Highlights

Extinction is a normal part of evolution, but human activity has accelerated the rate of species extinction.

Some extinct species once lived in our country, highlighting the loss to our local ecosystems.

All species play a vital role in the ecosystem through the food web.

Students were tasked with creating advocacy boards to propose projects to prevent human extinction.

Plants are crucial for life on Earth due to their role in the life cycle of all organisms.

Plants are a source of food for almost all organisms on the planet.

Plants provide resources for humans with aesthetic and economic benefits.

A single tree can provide food and shelter to many species.

Plants are involved in biogeochemical cycles, such as transpiration.

Photosynthesis maintains the Earth's atmosphere by producing oxygen and reducing carbon dioxide.

Plants and trees are important for providing shelter, food, clothing, and income sources.

Photosynthesis is a biological reaction that converts solar energy into glucose.

Visible light, particularly the green wavelength, powers photosynthesis.

Photosynthesis has two major steps: the light-dependent reactions and the light-independent reactions (Calvin cycle).

The chloroplast is the organelle that carries out photosynthesis.

Chlorophyll, the green pigment in plants, is responsible for light absorption in photosynthesis.

The light-dependent reactions occur in the thylakoids of the chloroplast.

The light-independent reactions or Calvin cycle occur in the stroma of the chloroplast.

The light-dependent reactions produce oxygen, ATP, and NADPH.

The Calvin cycle reduces carbon dioxide into glucose using the energy from ATP and NADPH.

Photosynthesis can be summarized by the formula: 6 CO2 + 6 H2O yields glucose + 6 O2.

The differences and similarities between light-dependent and light-independent reactions are highlighted.

A quiz is provided to test understanding of photosynthesis.

Encouragement is given for continuous learning and improvement in understanding photosynthesis.

Transcripts

last time we talked about species

extinction and we related it with the

failure of populations of organisms to

adjust to abrupt changes in the

environment

we also discussed that although

extinction is a normal part of evolution

rapid human modifications on the planet

have caused the extinction of more

species at an accelerated rate

we also learned about some extinct

species that once roamed our land and

lived in our country

finally we discovered that all species

play a vital role in the ecosystem

through the food web

wow

there were really interesting topics

we've discussed last episode

and i remembered giving you an activity

to make your advocacy board with the

programs or projects that you would like

to propose to avoid extinctions of human

beings

and here are the works of the three

grade nine learners about their

advocacies

good job students

today we will be talking about two

important biological reactions that

almost all organisms in this planet use

these are photosynthesis and cellular

respiration

in this episode we shall know each one

of them then later on we shall compare

them the question is why are plants so

important to us

the plant kingdom plays a crucial role

in the life cycle of all living things

for the following reasons

first

it is a source of food for almost all

organism in the planet

second it provide resources for humans

with aesthetic and economic benefits

such as provision for medicine

firewood fibers oils

rubber and many more

third

it provides habitats for different

organisms

do you know that a single tree can

provide food and shelter to many species

of insects worms small mammals birds and

reptiles

fourth because of its role in the

biogeochemical cycles an example of this

is the process of transpiration where

plants move water from the soil to the

atmosphere

and fifth

it maintains the earth's atmosphere

through photosynthesis

oxygen is essential for cellular

respiration for all aerobic organisms it

also maintains the ozone layer that

helps protect earth's life from the

damaging uv radiation

removal of carbon dioxide from the

atmosphere reduces the greenhouse effect

and global warming

plants and trees are very important

aside from the fact that they give

coloring beauty to our surroundings they

also provide us shelter food clothing

and sometimes they can also be our

sources of income hello there to all our

deer puntitos and plantitas more so they

perform a very important role in our

lives do you know that the role where i

refer to

they give off oxygen that we need

but how do plants give off oxygen

they do it through the biological

reaction of photosynthesis

this is made possible when plants take

in carbon dioxide and water from the air

and soil

within the plant cell the water is

oxidized meaning it loses electrons

while the carbon dioxide is reduced

meaning it gains electrons

this transforms the water into oxygen

and the carbon dioxide into glucose

the plant then releases the oxygen back

to the air and stores energy within the

glucose molecules

photosynthesis is a process of making

food for plants it involves the

following

energy from the sun

water carbon dioxide it will give off

oxygen and will also make simple sugar

like glucose

it may look simple but it's a bit

complex

let us try to look at the sun it gives a

variety of types of energy such as radio

wave microwave infrared visible

ultraviolet x-ray and gamma rays but we

will be focusing on the visible light

because it is the wavelength of visible

light that drives and powers

photosynthesis

visible light is also called white light

it is actually a mixture of royjib

red

orange

yellow green

blue indigo

violet or the colors of the rainbow

how is it so

try to use a white light in a prism and

a rainbow will appear

look at this example a blue shirt

appears blue because all the blue color

is reflected into our eyes and the other

colors are absorbed

a white shirt appears white because all

the color is reflected into our eyes and

nothing gets absorbed

a black shirt appears black because all

the color is absorbed and nothing is

reflected into our eyes the same thing

the color of the leaves appear green

because it will reflect the green

wavelength and will be absorbed by the

leaves and that is what powers

photosynthesis

we should remember that photosynthesis

is a process that converts solar energy

into glucose

this formula outlines photosynthesis

carbon dioxide plus water in the

presence of sunlight will yield glucose

and oxygen

where carbon dioxide and water are the

reactants and glucose and oxygen are the

by-products

photosynthesis has two major steps the

photo part and the synthesis part

the photo part is going to encompass the

light dependent reactions and the

synthesis part is going to be the light

independent reaction or the kelvin cycle

did you get it grade 9 learners

let us first discuss what a chloroplast

is

the chloroplast is an organelle that

carries out photosynthesis

let us look at each part of the

chloroplast

inside the chloroplast are thylakoids it

contains the green pigment of the plant

responsible for light absorption called

chlorophyll

one stack of thylakoid is called the

granum

multiple stacks of granum is called the

grana

the lumen is the fluid inside the

thylakoid

the stroma is the fluid inside the

chloroplast

the chloroplast has two membranes called

the inner membrane and the outer

membrane

while the space between them is called

the inter-membrane space

photosynthesis has two stages the light

dependent reactions which covers the

photo part and the light independent

reactions or the kelvin cycle also known

as the dark reactions

the light dependent reactions happen at

the thylakoids within the chloroplast

the light independent reactions or the

kelvin cycle however

occurs inside the stroma of the

chloroplast

why is it called a light independent

reactions

it is because it can proceed even

without light energy

the light dependent reactions oxidizes

water into oxygen gas

oops

the word oxidized makes me think of the

word oxidation

oxidation involves the loss of electrons

so whenever there is oxidation

there is always a reduction reaction

it is picked up by the nicotinamide

adenine dinucleotide phosphate or in

short nadp plus

where will nadp plus bring the electrons

it will be brought to the nadph or the

reduced form of nadp plus

some of the energy transferred by light

is used to make adenosine triphosphate

or

atp

from adp and phosphate

atp is produced by chemi osmosis using

an enzyme called

atp synthase

the products of light dependent

reactions are oxygen gas

atp

and nadph

while the reactants are the following

water

nadp plus

and adp plus p

now let us proceed to the light

independent reactions or the calvin

cycle also known as the dark reactions

in this type of reaction

it takes in carbon dioxide and reduces

it into glucose

carbon dioxide turned into glucose

is a reductive process

meaning to say

there must be an oxidation process

how

this time nadph

gives up its electrons and nadp plus

will gain it

carbon dioxide will receive its

electrons and eventually turn it into

glucose

what powers the calvin cycle

atp is responsible for powering the

calvin cycle process

in this process the atp is converted

back into adp plus b

so in the kelvin cycle

the reactants are carbon dioxide

atp

and nadph

while the products are glucose

nadp plus

adp plus b

to clearly understand the processes

involved in photosynthesis

let us simplify things by comparing the

light dependent and light independent

reactions

first of all let's talk about the

differences between the two

the first difference the two reactions

happen in different places

the light dependent reactions happen in

the thylakoid

while the light independent reactions

happen in the stroma

another point of contrast

light-dependent reactions require energy

from the sun

while light-independent reactions can

happen without the sun's energy

they also differ as far as their

reactants and products are concerned

the reactants of light dependent

reactions are

water

nadp plus

and adp

and phosphorus

while the products of the light

independent reactions are glucose

nad plus and adp plus p

and now let's go to their similarities

both of them require atp

both of them generate atp

both of them utilize the electron

transport chain through oxidation

reduction

both of them utilize the atp synthase to

power them

now it's time for you to test yourself

read each question carefully then write

the letter of your answer on a sheet of

paper

question number one

which of the following are the products

of photosynthesis

a

water and carbon dioxide

b

glucose and oxygen

c

carbon dioxide and glucose

or d

oxygen and water

question number two

light energy is absorbed by

a

thylakoid

b

grana

c

chlorophyll

or the inter membrane space

question number three

in what organelle of a plant cell does

photosynthesis take place

a

nucleus

b

mitochondria

c

cytoplasm

or d

chloroplast

question number four

which of the following is not true of

the calvin cycle

a

it requires sunlight

the

it happens at night

see

it takes in carbon dioxide and reduces

it into glucose

or d

it uses atp

question number five

what is the standard formula of

photosynthesis

a

six atoms of carbon dioxide plus six

atoms of water will yield glucose plus

six atoms of oxygen

b

six atoms of carbon dioxide plus six

atoms of water will yield glucose plus

six atoms of water

see

six atoms of carbon dioxide plus six

atoms of water will yield glucose plus

six atoms of oxygen

or d

six atoms of carbon dioxide plus six

atoms of carbon dioxide will yield

glucose plus six atoms of oxygen

depends up

let us answer the questions

question number one

which of the following are the products

of photosynthesis

the answer is

letter b

glucose and oxygen

question number two

light energy is absorbed by

the answer is

c

chlorophyll

question number three

what organelle of a plant cell does

photosynthesis

take place

the answer is

d

chloroplast

question number four

which of the following is not true of

the calvin cycle

the answer is

letter a it requires sunlight

question number five

what is the standard formula of

photosynthesis the answer is

letter a

six atoms of carbon dioxide plus six

atoms of water will yield glucose plus

six atoms of oxygen

how many of you got the correct answers

for all the items

for those who did not get to answer

everything correctly

you just need to remember that there is

always a room for improvement

just keep on trying

indeed there is much more to learn and

much more to explore and discover