Enzim dan Metabolisme Sel | Biologi SMA

Summary

This educational video script delves into the world of enzymes, highlighting their crucial role in daily life and biological processes. It explains that enzymes, produced by living cells, act as biological catalysts to expedite chemical reactions essential for the functioning of humans, animals, and plants. The script details the composition of enzymes, their optimal activity conditions, and specificity. It further explores the acceleration of chemical reactions by enzymes through reducing activation energy. The video also covers metabolism, distinguishing between catabolism, which breaks down complex molecules for energy, and anabolism, which constructs complex molecules from simpler ones. Specific examples include cellular respiration, both aerobic and anaerobic, and the processes of lipid and protein catabolism. Anabolism is exemplified by photosynthesis, converting carbon dioxide and water into glucose and oxygen. The script invites viewers to engage in a discussion on whether the 'dark reaction' of photosynthesis can occur during the day, encouraging interaction and further learning.

Takeaways

• 🍞 Enzymes are proteins that catalyze chemical reactions in living organisms, such as bread rising due to enzymatic action.
• 🧬 Our bodies utilize enzymes for digestion and cell growth, highlighting their essential role in biological processes.
• 🔬 Enzymes consist of an apoenzyme (protein component) and a prosthetic group, which can be a coenzyme or a cofactor.
• 🌟 Coenzymes are organic molecules, like vitamins, that transfer chemical groups, atoms, or electrons between enzymes.
• 🌿 Cofactors are inorganic ions or metal atoms that enhance enzyme function without being part of the enzyme's structure.
• 🌡 Enzymes operate optimally within specific temperature and pH ranges; extremes can lead to denaturation or inactivity.
• 🎯 Enzymes have an active site that specifically binds to certain substrates, exemplified by amylase acting only on starch.
• ♻️ Enzymes are reusable, as they remain unchanged after catalyzing reactions and are required in small quantities.
• 🔄 Enzymes can work in both forward and reverse reactions, such as maltase converting maltose to glucose and vice versa.
• 🚀 Enzymes speed up chemical reactions by lowering the activation energy needed for the reaction to occur.
• 🌱 Metabolism, the sum of all chemical reactions in a living cell, is facilitated by enzymes and includes both catabolic and anabolic processes.
• 🔋 Catabolism involves breaking down complex molecules into simpler ones to release energy, such as cellular respiration producing ATP from glucose.
• 🌳 Anabolism, on the other hand, builds complex molecules from simpler ones, requiring energy, like in photosynthesis converting carbon dioxide and water into glucose.

Q & A

What are enzymes and what is their role in our daily life?

Enzymes are protein compounds produced by living cells that function as biocatalysts to speed up chemical reactions. They are found in many aspects of our daily life, such as in the leavening of bread and in our bodies for digestion.

What are the components of an enzyme?

Enzymes are generally composed of an apoenzyme, which is the protein component, and a prosthetic group, which can be a coenzyme or a cofactor. Coenzymes are organic molecules like vitamins, and cofactors can be inorganic ions or metal atoms.

How do enzymes function as catalysts?

Enzymes function as catalysts by lowering the activation energy required for a chemical reaction to occur. They do this by binding to substrates in a way that resembles a lock and key mechanism, facilitating the reaction and then releasing the products.

What are the optimal conditions for enzyme activity?

Enzymes work optimally within specific ranges of temperature and pH. Too low temperatures can inactivate enzymes, while too high temperatures can cause them to denature.

Can you explain the specificity of enzymes?

Enzymes are specific, meaning they have an active site that works only with certain substrates. For example, the enzyme amylase can only work on the substrate amylum.

How are enzymes involved in metabolism?

Enzymes are involved in all chemical reactions within living cells that make up metabolism. Metabolism includes both catabolic processes, which break down complex molecules into simpler ones to produce energy, and anabolic processes, which build complex molecules from simpler ones, requiring energy.

What are the two types of cellular respiration and how do they differ?

There are two types of cellular respiration: aerobic and anaerobic. Aerobic respiration requires oxygen and breaks down glucose into carbon dioxide and water, producing 38 ATP. Anaerobic respiration does not require oxygen and includes processes like alcohol fermentation and lactic acid fermentation, producing 2 ATP.

What is the role of the citric acid cycle in cellular respiration?

The citric acid cycle, also known as the Krebs cycle, is a part of aerobic respiration that occurs in the mitochondria. It is where the breakdown of acetyl-CoA derived from glucose results in the production of ATP, NADH, and FADH2, which are used to generate more ATP.

How does the process of photosynthesis relate to enzyme activity?

Photosynthesis is an anabolic process that involves enzymes to convert carbon dioxide and water into glucose and oxygen. Enzymes play a crucial role in both the light-dependent reactions, where chlorophyll absorbs light energy, and the light-independent reactions, or the Calvin cycle, where CO2 is fixed into glucose.

Can you describe the process of glycolysis in cellular respiration?

Glycolysis is the first step of cellular respiration that occurs in the cytoplasm. It involves the breakdown of one molecule of glucose into two molecules of pyruvate, producing a small amount of ATP and NADH.

What is the role of ATP in metabolism?

ATP, or adenosine triphosphate, is the primary energy currency in metabolism. It is produced in catabolic processes and used in anabolic processes, providing the energy needed for various cellular activities.

Outlines

00:00

🧬 Enzymes: The Catalysts of Life

This paragraph introduces the concept of enzymes, emphasizing their ubiquity in daily life and their critical role in biological processes. Enzymes are proteins produced by living cells that act as biological catalysts, accelerating chemical reactions necessary for the functioning of humans, animals, and plants. They are composed of an apoenzyme (protein component) and a prosthetic group, which can be a coenzyme or a cofactor. Coenzymes are organic molecules like vitamins, while cofactors are inorganic ions or metal atoms that enhance enzyme function. Enzymes operate optimally within specific temperature and pH ranges, have an active site that binds substrates specifically, and can be reused multiple times without being consumed. They facilitate various metabolic processes, including catalysis in both directions. The paragraph also explains how enzymes work by lowering the activation energy required for chemical reactions and binding substrates in a lock-and-key mechanism. Metabolism, the set of chemical reactions within living cells, is facilitated by enzymes and includes both catabolism (breaking down complex molecules for energy) and anabolism (building complex molecules from simpler ones). Examples of catabolism include cellular respiration, which can be aerobic (requiring oxygen) or anaerobic (not requiring oxygen), and involves processes like glycolysis, oxidative decarboxylation, the Krebs cycle, and electron transport chain.

05:04

🍂 Metabolic Pathways and Enzymatic Functions

The second paragraph delves into the specifics of glucose catabolism, detailing the processes of glycolysis and fermentation, which yield 2 ATP each. It contrasts the production of ATP from carbohydrates with that from fats and proteins, highlighting that fats yield more ATP per molecule than carbohydrates. The paragraph also touches on the catabolism of proteins, which results in amino acids that undergo deamination before entering the respiratory pathway. Anabolism is exemplified by photosynthesis, a process that converts carbon dioxide and water into glucose and oxygen, occurring in the chloroplast's grana and stroma. The light-dependent reaction in grana uses chlorophyll to absorb light energy, producing oxygen, NADPH, and ATP, while the light-independent Calvin cycle in stroma uses these products to convert CO2 into glucose. The paragraph concludes with a question about the feasibility of the dark reaction occurring during the day and a prompt to visit kejarcita.id or download the kejarcita app for more practice on enzyme and cell metabolism topics.

Keywords

💡Enzyme

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are proteins produced by cells and play a crucial role in various bodily functions such as digestion and cell growth. In the script, enzymes are described as being involved in the expansion of bread and the digestion of food in our bodies, illustrating their relevance to everyday life and the video's theme of understanding enzymes and metabolism.

💡Apoenzym

An apoenzyme is the protein component of an enzyme that lacks the non-protein groups, known as prosthetic groups, needed for full activity. In the script, apoenzymes are mentioned as part of the enzyme structure, highlighting the complexity of enzymes and their requirement for specific components to function optimally.

💡Prosthetic Group

A prosthetic group is a non-protein component of an enzyme, such as a metal ion or an organic molecule, that is essential for the enzyme's activity. The script explains that prosthetic groups can be coenzymes or cofactors, which are vital for the enzyme's function, emphasizing the intricate nature of enzymatic reactions.

💡Coenzyme

A coenzyme is an organic, non-protein molecule that assists enzymes in their catalytic activity by transferring chemical groups, atoms, or electrons. In the script, coenzymes are mentioned as being composed of organic molecules like vitamins and playing a role in the transfer of chemical groups between enzymes, which is essential for metabolic processes.

💡Cofactor

A cofactor is a non-protein chemical that helps an enzyme function by enhancing its activity. The script describes cofactors as inorganic ions or metal atoms that are necessary for the enzyme to work, illustrating their importance in the biochemical reactions discussed in the video.

💡Active Site

The active site is the specific region of an enzyme where the substrate binds and the chemical reaction occurs. The script uses the analogy of a lock and key to describe how the active site fits the substrate, highlighting the specificity of enzyme-substrate interactions and their role in catalyzing reactions.

💡Substrate

A substrate is the molecule upon which an enzyme acts to catalyze a chemical reaction. The script mentions that enzymes are specific to their substrates, such as amylase acting on starch, which is crucial for understanding the specificity of enzymatic reactions and their role in metabolism.

💡Metabolism

Metabolism refers to the set of life-sustaining chemical reactions in cells, including both anabolic (building up) and catabolic (breaking down) processes. The script discusses metabolism in the context of enzyme-catalyzed reactions, emphasizing the central role of enzymes in maintaining life functions.

💡Catabolism

Catabolism is the process of breaking down complex molecules into simpler ones, often releasing energy. The script provides examples of catabolic processes like cellular respiration and the breakdown of glucose, fats, and proteins, which are essential for generating energy within cells.

💡Anabolism

Anabolism is the set of metabolic processes that construct complex molecules from simpler ones, typically requiring energy. The script contrasts anabolism with catabolism and gives the example of photosynthesis, where carbon dioxide and water are converted into glucose and oxygen, illustrating the building-up aspect of metabolism.

💡Fermentation

Fermentation is an anaerobic process that converts sugar to acids, gases, or alcohol, often used by cells to generate energy in the absence of oxygen. The script describes two types of fermentation: alcoholic and lactic acid fermentation, which are part of the catabolic breakdown of glucose, providing a clear example of how enzymes facilitate these energy-yielding reactions.

Highlights

Enzymes are abundant in our daily lives, such as in bread leavening and digestion.

Enzymes are protein compounds produced by living cells that act as biocatalysts to speed up chemical reactions.

Enzymes assist the body in various tasks, including digestion and cell renewal.

Enzymes consist of an apoenzyme or protein component and a prosthetic group.

Prosthetic groups can be coenzymes or cofactors, with coenzymes made up of organic molecules like vitamins.

Coenzymes function by transferring chemical groups, atoms, or electrons between enzymes.

Cofactors are inorganic ions or metal atoms that enhance enzyme function.

Enzymes operate optimally within specific temperature and pH ranges.

Extremely low temperatures can inactivate enzymes, while high temperatures may cause denaturation.

Enzymes have an active site that works specifically or only on certain substrates.

Enzymes can be used repeatedly as they do not react and are needed in small quantities.

Enzymes generally work bidirectionally, such as maltase converting maltose to glucose and vice versa.

Enzymes speed up chemical reactions by reducing activation energy.

The active site of an enzyme binds to the substrate like a lock and key or flexibly adapts to the substrate's shape.

Metabolism is the sum of all chemical reactions in living cells aided by enzymes.

Catabolism breaks down complex molecules into simpler ones to produce energy.

Anabolism is the process of building complex molecules from simpler ones, requiring energy.

Cellular respiration is an example of catabolism, aimed at producing energy in the form of ATP.

Aerobic respiration requires oxygen and anaerobic respiration does not.

Aerobic respiration involves glycolysis, oxidative decarboxylation, the Krebs cycle, and electron transport.

Anaerobic respiration includes alcohol fermentation and lactic acid fermentation, both using glucose.

Fats are broken down into fatty acids and glycerol, which then enter the respiratory pathway.

Proteins are broken down into amino acids, which undergo deamination before entering the respiratory pathway.

Photosynthesis is an example of anabolism, converting carbon dioxide and water into glucose and oxygen.

The light-dependent reactions of photosynthesis occur in the grana of chloroplasts.

The light-independent reactions, or Calvin cycle, convert CO2 into glucose using ATP and NADPH.

Can the dark reactions of photosynthesis occur during the day?

Transcripts

Enzim banyak ditemukan dalam kehidupan sehari-hari kita.

Misalnya, roti bisa mengembang karena pengaruh enzim,

tubuh kita pun memanfaatkan enzim untuk mencerna makanan.

Tetapi tahukah kamu apa itu enzim dan manfaatnya?

Enzim adalah senyawa protein yang dihasilkan oleh sel-sel makhluk hidup dan berfungsi sebagai biokatalisator untuk mempercepat reaksi kimia.

Reaksi ini adalah proses yang memungkinkan manusia, hewan, dan tumbuhan berfungsi.

Enzim membantu tubuh kita melakukan berbagai tugas, seperti mencerna dan menumbuhkan sel-sel baru.

Enzim umumnya tersusun atas apoenzim atau komponen protein dan gugus prostetik.

Gugus prostetik dapat berupa koenzim maupun kofaktor.

Koenzim tersusun atas molekul organik, seperti vitamin dan koenzim A.

Koenzim berfungsi untuk memindahkan gugus kimia, atom, atau elektron dari satu enzim ke enzim lainnya.

Sedangkan kofaktor tersusun atas ion anorganik atau atom logam yang berfungsi untuk meningkatkan fungsi enzim.

Enzim memiliki beberapa sifat sebagai berikut:

Enzim hanya bekerja optimal pada kisaran suhu dan ph tertentu.

Suhu yang terlalu rendah akan membuat enzim tidak aktif,

sedangkan suhu yang terlalu tinggi dapat menyebabkan enzim rusak atau mengalami denaturasi.

Enzim memiliki sisi aktif yang bekerja secara spesifik atau hanya bekerja pada substrat tertentu.

Contohnya enzim amilase hanya dapat bekerja pada substrat amilum.

Enzim dapat digunakan berulang kali karena enzim tidak ikut bereaksi dan hanya diperlukan dalam jumlah yang sedikit.

Umumnya, enzim dapat bekerja bolak-balik atau dua arah.

Contohnya enzim maltase dapat mengubah maltosa menjadi glukosa.

Begitu juga sebaliknya, mengubah glukosa menjadi maltosa kembali.

Lalu, bagaimana cara enzim bekerja untuk mempercepat reaksi kimia?

Enzim mempercepat reaksi dengan cara menurunkan energi aktivasi.

Energi aktivasi adalah energi minimum yang dibutuhkan agar reaksi kimia dapat terjadi.

Sisi aktif enzim akan mengikat substrat seperti gembok dan anak kuncinya atau fleksibel menyesuai bentuk substratnya.

Setelah substrat berubah menjadi produk, enzim akan dilepas kembali.

Seperti diketahui, enzim dapat mempercepat suatu reaksi kimia.

Jadi, reaksi apa saja yang akan dibantu oleh enzim?

Metabolisme merupakan keseluruhan reaksi kimia dalam sel makhluk hidup yang dibantu oleh enzim.

Terdapat dua proses dalam metabolisme, yaitu katabolisme dan anabolisme.

Katabolisme adalah pemecahan senyawa kompleks menjadi senyawa sederhana yang akan menghasilkan energi.

Sebaliknya, anabolisme adalah rangkaian proses penyusunan senyawa kompleks dari senyawa sederhana yang memerlukan energi.

Contoh katabolisme adalah respirasi sel.

Tujuan dari respirasi adalah untuk menghasilkan energi dalam bentuk ATP,

yang akan digunakan untuk melakukan aktivitas.

Berdasarkan kebutuhannya terhadap oksigen, respirasi sel ini terbagi menjadi dua,

yaitu respirasi aerob yang membutuhkan oksigen dan respirasi anaerob yang tidak membutuhkan oksigen.

Respirasi aerob akan memecah senyawa glukosa menjadi karbon dioksida dan air.

Total energi yang dihasilkan adalah 38 ATP.

Dalam prosesnya, respirasi aerob memiliki urutan mulai dari

Glikolisis, Dekarboksilasi oksidatif, Siklus Krebs, dan yang terakhir rantai transpor elektron.

Glikolisis terjadi di sitosol,

sedangkan tahapan selanjutnya terjadi di mitokondria.

Adapun respirasi anaerob terdiri dari fermentasi alkohol dan fermentasi asam laktat.

Keduanya menggunakan substrat glukosa.

Pada tahap awal, glukosa akan mengalami glikolisis menghasilkan 2 asam piruvat.

Kemudian pada fermentasi alkohol, asam piruvat akan melepas CO2 menjadi asetaldehida dan asetaldehida direduksi menjadi etanol atau alkohol.

Adapun pada fermentasi asam laktat, asam piruvat akan langsung direduksi menjadi asam laktat.

Proses fermentasi ini akan menghasilkan 2 ATP.

Selain katabolisme glukosa atau karbohidrat, ada juga proses katabolisme lemak dan protein.

Lemak akan dipecah menjadi asam lemak dan gliserol.

Selanjutnya, asam lemak dan gliserol akan masuk ke jalur respirasi.

Setiap 1 molekul lemak, akan menghasilkan 46 ATP, lebih besar daripada yang dihasilkan oleh karbohidrat.

Adapun protein akan dipecah menjadi asam amino.

Asam amino kemudian mengalami pelepasan nitrogen atau deaminasi.

Bahan yang tersisa kemudian akan masuk ke jalur respirasi.

Satu molekul protein akan menghasilkan 38 ATP, sama seperti karbohidrat.

Selanjutnya apa contoh proses anabolisme?

Contohnya adalah reaksi fotosintesis, yang mengubah karbon dioksida dan air menjadi senyawa glukosa dan oksigen.

Proses ini terjadi pada organel kloroplas, tepatnya pada dua bagian utama, yaitu grana dan stroma.

Grana terbungkus oleh membran tilakoid dan mengandung klorofil.

Klorofil inilah yang berperan dalam penyerapan cahaya.

Pada grana, proses fotosintesis membutuhkan cahaya sehingga disebut reaksi terang.

Adapun pada stroma, prosesnya tidak membutuhkan cahaya sehingga disebut reaksi gelap.

Pada reaksi terang, air dipecah menjadi oksigen dengan bantuan energi cahaya.

Selain itu, dibentuk juga NADPH dan energi ATP.

Kemudian, pada reaksi gelap atau siklus Calvin, CO2 akan diubah menjadi glukosa dengan melibatkan ATP dan NADPH.

Nah, teman-teman itulah penjelasan terkait enzim dan metabolisme sel.

Menurutmu, apakah reaksi gelap dapat berlangsung pada siang hari?

Coba tuliskan jawabanmu di kolom komentar ya.

Kalau mau latihan soal topik Enzim dan Metabolisme Sel,

yuk kunjungi website kejarcita.id atau download aplikasi kejarcita di playstore.

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