Molecular Biology

What is molecular biology?

-Molecular biology is the study of biology at a molecularlevel.

-The field overlaps with other areas of biology, particularlygenetics and biochemistry.

-Molecular biology chiefly concerns itself withunderstanding the interactions between the various systems

of a cell.

Is this an animal or plant cell? Explain.“Cell Structure & Function” 10:36

Plant Cell: How do plant and animal cells differ?

Organelles have specific functions.• Lysosome: contains enzymes that break down nutrients, wastes, bacteria and worn

out cell parts

• Ribosome: take information from DNA and use it to make proteins

• Vacuole: a membrane-bound sac that plays roles in intracellular digestion and the

storage and release of cellular waste products

• Nucleus: a large, oval structure that directs all of the cell’s activities; houses

genetic material

• Mitochondria: produce most of the energy/ATP the cell needs to carry out its

functions; where respiration occurs

• Golgi Body (apparatus): receives and packages products, including proteins, for

use in the cell

• Endoplasmic Reticulum: where chemical reactions take place; a system whose

functions include synthesis and transport of lipids and, in regions

where ribosomes are attached, of proteins

• Cell Membrane: forms the outside boundary that separates the cell from its

environment; controls what enters and leaves the cell

• Cytoplasm: the region between the cell membrane and the nucleus

• Cell Wall: plant; rigid structure that gives the cell shape - Gizmo: “Cell Structure”- Matching activity

What is “food”?• material or molecules that provide living things with

the nutrients they need for energy and growth

Foods with natural sugars (carbs) tend to be the healthiest for you.

And Carbohydrates(simple & complex carbs)

Food provides molecules that serve as fuel and building material. (see compound PowerPoint)

• What is a molecule? The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms; a group of like or different atoms held together by chemical forces.

The substance (compound) here is water. It is made up of oxygen (1 atom) and hydrogen (2 atoms). H2O (chemical formula for 1 molecule of water)

+

+

-- Water is a polar molecule because it has electrically/oppositely charged areas.

- Water is not considered “food” because it does not provide the body with energy.

What “biological compounds do our cells need?

The four major biological compounds are:• Proteins (key for building body tissues; aim for 10% to 35%

of calories)• Nucleic Acids (RNA and DNA)• Carbohydrates (fuels our brain and muscles; energy source

- aim for 45% to 65% of calories) • Lipids (contributes essential fatty acids and promotes

absorption of fat-soluble vitamins A,D,E, and K; energy source – aim for 20% to 35% of calories – mostly unsaturated)

- Only proteins, carbohydrates and lipids are considered “food” because they are the only ones in which the body/cells get energy.

• http://www.youtube.com/watch?v=H8WJ2KENlK0 “Biological Molecules: You are what you eat.” 14:09

What is “protein”?

• One of the three nutrients used as energy sources (calories) by the body.

• Proteins are essential components of the muscle,

skin, and bones.

• aim for 10% to 35% of calories

• Proteins and carbohydrates each provide 4 calories of energy per gram, whereas fats provide 9 calories per gram.

Top 10 Plants High in Protein

#1 asparagus #2 pumpkin seeds #3 cauliflower #4 peanuts

#5 oats #6 beans #7 almonds

#8 spinach #9 broccoli #10 quinoa

Simple vs Complex Carbs

Carbohydrates and fats are the main source of energy for your body. Carbs are made up of sugars, which break down to provide either quick energy or slow-burning, sustained energy over a period of several hours. "Simple" carbs are quick energy sources, while "complex" carbs provide longer-lasting energy. In addition to providing physical energy, carbohydrates also effectively fuel the brain.

What are lipids/fats?

• a biological compound that is not soluble (dissolvable) in water, e.g. a fat.

• Fats are classified as “saturated ” or “unsaturated .

• Unsaturated fats are more beneficial to our body and are liquid at room temperature.

• Saturated fats are less beneficial to our bodies and are solid at room temperature.

• “Trans Fats” are a type of unsaturated fat that is not beneficial to our bodies.

• Lipids/fats have more energy; however, unsaturated fats are healthy.

The Real Story on Fats!

Are fats good or bad for you? What do you think?

Unsaturated Fats VS Saturated Fats

Effects of Long-term Consumption of Saturated Fats - Eating fatty foods appears to take an

almost immediate toll on both short-term memory and exercise performance.

- Studies have suggested that long-term consumption of a high-fat diet is associated with weight gain, heart disease and declines in cognitive (mental) function.

-New research shows how indulging in-fatty foods over the course of a few-days can affect the brain and body long before the extra pounds show up.

Plants and Food Production• The three major functions that are basic

to plant growth and development are:

• Photosynthesis – The process of capturing light energy and converting it to sugar energy, in the presence of chlorophyll using carbon dioxide and water. (releasing O2 and H2O)

• Respiration – The process of metabolizing (burning) sugars to yield energy for growth, reproduction, and other life processes. (releasing H2O and CO2)

• Transpiration – The loss of water vapor through the stomata of leaves.

(CO2)

(H2O)

(O2)

“Respiration & Excretion” 9:16

In photosynthesis…

- carbon dioxide from the air and water from the soil react with the sun’s energy to form sugars, starches, proteins, and carbohydratesand release oxygen as a byproduct.

- the plant uses water and nutrients from the soil, and carbon dioxide from the air with the sun’s energy. Oxygen is released as a byproduct.

- Photosynthesis literally means to put together with light. It occurs only in the chloroplasts, tiny sub cellular structures contained in the cells of leaves and green stems.

The chemical equation for photosynthesis is:

6CO2 + 6H2O+ light energy = C6H12O6 + 6O2

The word equation for photosynthesis is:

carbon dioxide + water + light energy = glucose + oxygen

Respiration in Plants• In respiration, plants (and animals) convert the sugars back into energy for growth and

other life processes (metabolic processes). • A simple chemical equation for respiration is given below. Notice that the equation for

respiration is the opposite of that for photosynthesis.

The word equation for aerobic respiration is:- glucose + oxygen = carbon dioxide + water + energy

The chemical equation is:

- C6H12O6 + 6O2 = 6CO2 + 6H2O + 2900 kj

Chemically speaking, the process is similar to the oxidation that occurs as wood is burned, producing heat. When compounds combine with oxygen, the process is often referred to as “burning”, for example, athlete’s “burn” energy (sugars) as they exercise. The harder they exercise, the more sugars they burn so the more oxygen they need. That is why at full speed, they are breathing very fast. Athletes take in oxygen through their lungs.

At night, plants take in a small amount of oxygen through the stomata in their leaves and through their roots.

Do plants take in oxygen (O2)?

• All plants and animals on earth engage in a process called respiration.

• One of the byproducts of respiration is carbon dioxide. In other words, respiration is the opposite of photosynthesis.

Respiration• Respiration doesn’t depend on light; it goes on 24 hours a day, so that plants and

animals have enough energy to perform the basic functions that keep them alive.• However, during the day, the amount of oxygen plants release as part of

photosynthesis makes the amount of oxygen they consume for respiration at night seem negligible.

Nighttime Battle?• At night, when photosynthesis can’t take place, plants continue to consume

oxygen but they don’t release any back into the atmosphere. • The amount of oxygen the plants use at night is trivial.

Comparing Photosynthesis and Respiration Photosynthesis Respiration

- Produces sugars from light

energy

- Stores energy

- Occurs only in cells with

chloroplasts

- Releases oxygen

- Uses water

- Uses carbon dioxide

- Requires light

- Burns sugars for energy

- Releases energy

- Occurs in most cells

- Uses oxygen

- Releases water

- Produces carbon dioxide

- Occurs in darkness and light

(Yeast Respiration lab)

What are the waste products of photosynthesis? (dissolved O2 demo.)

What are the waste products of respiration?

Transpiration in Plants

- Water in the roots is pulled through the plant by transpiration (loss of water vapor through the stomata of the leaves).

- Transpiration uses about

90% of the water that enters the plant. The other 10% is an ingredient in photosynthesis and cell growth.

The capillary action of water molecules keep water moving up the roots and through the plant.

Transpiration

After securing the bag on the plant, water is captured as it travels out the leaves of the plant..

1. What is the process that leads to transpiration?2. What are the waste products of photosynthesis?

What is “chemical energy”?

•Consider the ability of your body to do work.

•The glucose (blood sugar) in your body is said to have "chemical energy" because the glucose releases energy when chemically reacting (combusting) with oxygen.

Food provides molecules that serve as fuel and building material for all organisms.

- Plants use the energy in light to make sugars out of carbon dioxide and water through a process called photosynthesis.

- This process transforms light energy from the sun into stored chemical energy. Chemical energy is transferred from one organism in an ecosystem to another as they interact with each other for food.

- Minerals and other nutrients from soil are not food (They don’t provide energy.), but are needed for plants to make complex molecules from the sugar they make.

Matter is transferred among organisms.

• Molecules from food react with oxygen to produce carbon dioxide (CO2) and water in a process called cellular respiration.

• Through the process of cellular respiration, cells convert energy (glucose) to a usable form of energy (ATP).

• Energy stored in ATP enables cells to grow, develop, repair organisms, locomotion and transportation of molecules across the cell membrane.

• Some plants (like legumes - i.e. peas) form a relationship with microorganisms. This happens in their roots, and nodules are formed. These microbes can take nitrogen from the air (which is about 80% nitrogen) and turn it into ammonia, which is absorbed by the plant’s root.

• Animals get nitrogen by eating other plants or animals, which contain protein (which is made of nitrogen and other things). Nitrogen is a component in both protein and chlorophyll.

In plant and animals, molecules from food:

(1) react with oxygen to provide energy that is needed to carry out life functions;

(2) build and become incorporated into the body structure or

(3) are stored for later use.

Food is the “fuel” for our bodies. How do animals convert food to energy?

• Mitochondria are the converters; they convert the fuel into useable energy.

• When food is digested, or broken down into its smallest molecules and nutrients, and air is taken in, the smallest molecules and nutrients cross into the bloodstream. These molecules and nutrients include things such as glucose (a sugar molecule derived from carbohydrates) and oxygen.

• You will consume more fuel than is necessary to make the machine called your body function. The excess gets stored for later as fat.

• Just as fire burns oxygen and gives off carbon dioxide and water, mitochondria act like furnaces when they convert glucose into adenosine triphosphate (ATP): They “burn” (use) oxygen and give off carbon dioxide and water in a process called respiration. Because the process uses oxygen, it is said to be aerobic (as in aerobic exercise).

• This chemical process of respiration occurs in every cell, so it is called aerobic cellular respiration.

What is metabolism?

• Metabolism is the energy (calories) your body needs to function, and it operates at a different rate for each person.

• This involves a set of chemical reactions that store fuel (food) molecules and convert them into energy. In order for the body to use the fuel energy stored in food, the food must first be digested and combined with oxygen (oxidized).

Three factors contribute to the overall metabolic rate of the body.

1. Basal Metabolic Rate (BMR) accounts for about 60% of all energy used by the body.

2. Daily physical activities account for another 30% of the energy used by the body.

3. 10% of the energy used by the body is used to digest and process (oxidize) food.

ENERGY IN = ENERGY OUT

1. In order for energy balance to occur, caloric intake equals caloric output.

2. What happens to food components (protein, fat/lipids,carbohydrates taken into the body:

They can be used to fuel metabolic activities and physical activities.

They can be incorporated into growing body tissues.

They can be stored as fat.

What affect does exercise have on metabolism?