https://www.khanacademy.org/science/ms-biology/x0c5bb03129646fd6:cells-and-organisms/x0c5bb03129646fd6:cells-organisms/v/ms-cells-and-organisms 2022-09-10T03:04:58.582913383Z Cells and organisms All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular). Khan Academy video https://cdn.kastatic.org/ka_thumbnails_cache/4c87c6c9-4669-4319-91b7-935603e64401_1280_720_base.png Cells and organisms All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular). https://cdn.kastatic.org/ka-youtube-converted/Uiqro5TUyLA.mp4/Uiqro5TUyLA.mp4 237 The Invisible Living World: Beyond Our Naked Eye https://www.khanacademy.org/science/ncert-class-8-science/x55541eeaec8b3a9a:microorganisms-friend-and-foe/x55541eeaec8b3a9a:what-is-a-cell/v/cell-size-dubv 2025-05-29T08:44:44.739717086Z Cell size Let's think about the limiting factors of cell size. Focus on volume to surface area ratio. Dubverse video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Cell size Let's think about the limiting factors of cell size. Focus on volume to surface area ratio. https://cdn.kastatic.org/ka-youtube-converted/Bf7ipaOXMgU.mp4/Bf7ipaOXMgU.mp4 536 The Invisible Living World: Beyond Our Naked Eye https://www.khanacademy.org/science/ncert-class-8-science/x55541eeaec8b3a9a:microorganisms-friend-and-foe/x55541eeaec8b3a9a:types-of-cells/v/types-of-cells 2025-07-03T11:03:56.817450545Z Types of cells What are cells, and why do they come in different shapes and sizes? In this video, we’ll explore the various types of cells and how their structure helps them do specific jobs in the body. You’ll learn why some cells are long, some are round, and others are tiny or large—and how these differences are important for how they work. Vibhor Pandey video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Types of cells What are cells, and why do they come in different shapes and sizes? In this video, we’ll explore the various types of cells and how their structure helps them do specific jobs in the body. You’ll learn why some cells are long, some are round, and others are tiny or large—and how these differences are important for how they work. https://cdn.kastatic.org/ka-youtube-converted/Z8wtQuiCwD8.mp4/Z8wtQuiCwD8.mp4 880 The Invisible Living World: Beyond Our Naked Eye https://www.khanacademy.org/science/ms-biology/x0c5bb03129646fd6:cells-and-organisms/x0c5bb03129646fd6:organization-in-the-human-body/a/organization-in-the-human-body 2026-06-30T14:20:41.927190319Z Key points: Organization in the human body Review your understanding of organization in the human body in this free article. article https://www.khanacademy.org/science/revision-term-2-tg-biology-class-8/x04828215b460a495:week-2/x04828215b460a495:the-world-of-microorganisms-part-i-ii/v/classification-understanding-microorganism-middle-school-science-khan-academy 2025-01-08T02:29:38.725066879Z Classification of Microorganisms Discover how microorganisms are grouped into categories like bacteria, fungi, algae, protozoa, and viruses based on their shape, structure, and life processes. Shankar Nair video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Classification of Microorganisms Discover how microorganisms are grouped into categories like bacteria, fungi, algae, protozoa, and viruses based on their shape, structure, and life processes. https://cdn.kastatic.org/ka-youtube-converted/Q-eLlmnf72g.mp4/Q-eLlmnf72g.mp4 444 The Invisible Living World: Beyond Our Naked Eye https://www.khanacademy.org/science/od-science-class-8-revision-term-1/xda08a8a5103044e1:week-4/xda08a8a5103044e1:the-invisible-living-world-beyond-our-naked-eye/e/revision-cells 2026-08-07T11:20:58.434105105Z Revision: cells Lets answer some questions. Shankar R exercise https://www.khanacademy.org/science/od-science-class-8-revision-term-1/xda08a8a5103044e1:week-4/xda08a8a5103044e1:the-invisible-living-world-beyond-our-naked-eye/e/revision-cell-structure-and-their-functions 2026-08-07T11:20:58.434105105Z Revision: Cell structure and their functions. Lets answer some questions. Shankar R exercise https://www.khanacademy.org/science/od-science-class-8-revision-term-1/xda08a8a5103044e1:week-4/xda08a8a5103044e1:the-invisible-living-world-beyond-our-naked-eye/e/revision-understand-cells-and-organisms 2026-08-07T11:20:58.434105105Z Revision: Understand: Cells and organisms lets answer some questions Shankar R exercise https://www.khanacademy.org/science/od-science-class-8-revision-term-1/xda08a8a5103044e1:week-4/xda08a8a5103044e1:the-invisible-living-world-beyond-our-naked-eye/e/revision-organization-in-the-human-body 2026-08-07T11:20:58.434105105Z Revision: Organization in the human body Lets answers some questions. Shankar R exercise https://www.khanacademy.org/science/od-science-class-8-revision-term-1/xda08a8a5103044e1:week-4/xda08a8a5103044e1:the-invisible-living-world-beyond-our-naked-eye/e/revision-how-are-we-connected-to-microbes 2026-08-07T11:20:58.434105105Z Revision: How are we connected to Microbes? Lets answer some questions. Shankar R exercise https://www.khanacademy.org/science/od-science-class-8-revision-term-1/xda08a8a5103044e1:week-4/xda08a8a5103044e1:the-invisible-living-world-beyond-our-naked-eye/e/revision-method-of-food-protection 2026-08-07T11:20:58.434105105Z Revision: Method of food protection Lets answer some questions. Shankar R exercise https://www.khanacademy.org/science/od-science-class-8-revision-term-1/xda08a8a5103044e1:week-4/xda08a8a5103044e1:the-invisible-living-world-beyond-our-naked-eye/e/revision-micro-organisms-fundamentals 2026-08-07T11:20:58.434105105Z Revision: Micro-organisms (Fundamentals) lets answer some questions. Shankar R exercise https://www.khanacademy.org/science/revision-term-2-tg-biology-class-8/x04828215b460a495:week-2/x04828215b460a495:the-world-of-microorganisms-part-i-ii/v/food-protection-preservation-part-1 2024-12-29T07:21:40.948705593Z Food Protection & Preservation Part-1 In this video, we’ll dive into the amazing techniques we use every day to keep food safe and fresh. Shankar Nair video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Food Protection & Preservation Part-1 In this video, we’ll dive into the amazing techniques we use every day to keep food safe and fresh. https://cdn.kastatic.org/ka-youtube-converted/YrMjjX-M0o0.mp4/YrMjjX-M0o0.mp4 382 The Invisible Living World: Beyond Our Naked Eye https://www.khanacademy.org/science/class-7-science/x0c8b40bd4b242f0b:food-health-and-disease/x0c8b40bd4b242f0b:methods-of-preservation/v/food-protection-preservation-part-2 2024-12-29T07:21:40.948705593Z Food Protection & Preservation Part-2 In this video, we’ll uncover advanced techniques like the use of inert gases and radiation to keep food safe and fresh. Shankar Nair video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Food Protection & Preservation Part-2 In this video, we’ll uncover advanced techniques like the use of inert gases and radiation to keep food safe and fresh. https://cdn.kastatic.org/ka-youtube-converted/F5uCuKP-_m4.mp4/F5uCuKP-_m4.mp4 332 The Invisible Living World: Beyond Our Naked Eye https://www.khanacademy.org/science/revision-term-2-tg-biology-class-8/x04828215b460a495:week-2/x04828215b460a495:the-world-of-microorganisms-part-i-ii/v/nitrogen-fixing-middle-school-science-khan-academy 2025-03-06T03:29:07.687997642Z Nitrogen Fixing Ever wondered why plants need nitrogen but can’t just take it from the air? Shankar Nair video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Nitrogen Fixing Ever wondered why plants need nitrogen but can’t just take it from the air? https://cdn.kastatic.org/ka-youtube-converted/iQmLJ6zZxcI.mp4/iQmLJ6zZxcI.mp4 411 The Invisible Living World: Beyond Our Naked Eye https://www.khanacademy.org/science/revision-term-2-tg-biology-class-8/x04828215b460a495:week-2/x04828215b460a495:the-world-of-microorganisms-part-i-ii/v/nitrogen-cycle-middle-school-science-khan-academy 2025-03-06T03:29:07.687997642Z Nitrogen Cycle Did you know that nitrogen keeps moving through the air, soil, plants, and animals in a never-ending cycle? Shankar Nair video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Nitrogen Cycle Did you know that nitrogen keeps moving through the air, soil, plants, and animals in a never-ending cycle? https://cdn.kastatic.org/ka-youtube-converted/rDFVzVOkcPs.mp4/rDFVzVOkcPs.mp4 256 The Invisible Living World: Beyond Our Naked Eye https://www.khanacademy.org/science/od-science-class-8-revision-term-1/xda08a8a5103044e1:week-4/xda08a8a5103044e1:the-invisible-living-world-beyond-our-naked-eye/e/revision-nitrogen-fixing-and-nitrogen-cycle 2026-08-07T11:20:58.434105105Z Revision: Nitrogen fixing and nitrogen cycle Lets answer some question. Shankar R exercise