Through the process of cellular respiration, the energy in food is converted into energy that can be used by the body’s cells. During cellular respiration, glucose and oxygen are converted into carbon dioxide and water, and the energy is transferred to ATP.

Cellular respiration can produce up to 32 ATP molecules for each glucose molecule, a capture of about 34% of the energy originally stored in glucose. The rest of the energy is lost as heat (see Module 5.10).

Energy contained in the bonds of glucose is released in small bursts, and some of it is captured in the form of adenosine triphosphate (ATP), a small molecule that powers reactions in the cell. Much of the energy from glucose is dissipated as heat, but enough is captured to keep the metabolism of the cell running.

Respiration releases energy – it is an exothermic process. The energy is stored in molecules of ATP . ATP can be broken down in other processes in cells to release the stored energy. Don’t confuse respiration with photosynthesis.

All living things need energy. Without it, they cannot grow, or move, or produce young. Animals need energy to grow and reproduce. They use light energy to make their own food.

Animals use energy for many different things. They need energy to grow, to move, to keep themselves warm and to heal their body when it gets hurt or sick. Where does the energy that animals use come from? (Allow the students to answer.)

Energy is passed between organisms through the food chain. Plants harvest their energy from the sun during photosynthesis. This energy can then be passed from one organism to another in the food chain. The organism that obtains energy from sunlight is called the producer.

Animals either eat plants to obtain chemical energy in the form of glucose or they eat other animals that ate plants. Energy moves from the Sun to plants to animals. Photosynthesis is necessary for that energy flow.

Animals—like the deceased monitor lizard in this video—are a source of energy-rich food even after they die. Here we can see beetles, flies, bacteria, and other organisms feasting the lizard’s carcass. They get their energy from rotting flesh, just as we get energy from the food we eat.

All energy for life on Earth comes from the sun. After the energy leaves the sun it is used by plants on Earth where photosynthesis converts it to sugars. The plants store chemical energy that can be used by the plants, or converted into mechanical energy within an organism (e.g. an animal which eats the plant.)

Animals don’t need energy from the sun, not directly anyway. Animals get energy from the food they eat. However, that food either got its energy by eating other food, or by photosynthesis, and sooner or later almost all energy on Earth comes from the sun.

That’s because almost all living things rely on the steady light and heat of the Sun. The Sun’s heat makes liquid water on our planet possible. And all life that we know of — from bacteria to elephants — needs liquid water to survive. Changes in the Sun’s brightness can change global temperatures.

Excessive exposure to the sun is known to be associated with increased risks of various skin cancers, cataracts and other eye diseases, as well as accelerated skin ageing. It may also adversely affect people’s ability to resist infectious diseases, and compromise the effectiveness of vaccination programmes.

Sunlight and darkness trigger the release of hormones in your brain. Exposure to sunlight is thought to increase the brain’s release of a hormone called serotonin. Serotonin is associated with boosting mood and helping a person feel calm and focused.

Our body creates vitamin D from direct sunlight on our skin when we’re outdoors.

If you wear clothing that covers most of your skin, you may be at risk for vitamin D deficiency. This also means that people who train indoors during winter months may have to dig into their bodies’ vitamin D stores if they don’t consume enough, which further increases their risk for deficiency.

Regular sun exposure is the most natural way to get enough vitamin D. To maintain healthy blood levels, aim to get 10–30 minutes of midday sunlight, several times per week. People with darker skin may need a little more than this. Your exposure time should depend on how sensitive your skin is to sunlight.

Not many realise that It’s only the early morning sun — that is, from 7 am to 9 am — that helps generate Vitamin D. After 10 am, exposure to sunlight is harmful for the body.

Try to stay out of the direct sun between 10 a.m. and 4 p.m., when the sun’s rays are strongest, and take breaks inside.

Use of sunscreen. Sunscreen prevents sunburn by blocking UVB light. Theoretically, that means sunscreen use lowers vitamin D levels.

The skin produces more vitamin D when in the sun during the middle of the day, the time it is at its highest point in the sky. When spending prolonged time in the hot sun, wear sunscreen, and stay hydrated. Amount of skin exposed. The more skin a person exposes, the more vitamin D the body will make.

Here are five ways to protect your skin without sunscreen:

1. Clothing. Long sleeves and pants offer protection, especially when the fabrics are closely knit and dark.
2. UV-repellent detergent.
3. Sunglasses.
4. Outdoor smarts.
5. Avoiding UV lights.