Chapter 5

Questions :

What do we need enzymes for ?

Enzymes are proteins that function as biological catalysts. What that means is for every reaction in our bodies we need certain energy which is called activation energy (Ea). What enzymes do is that they decrease this activation energy without being consumed by the reaction. So in the end we need enzymes to help our body be more efficient and to be able to process more biological reaction with less energy.

What are the Thermodynamic laws ?

thermodynamic is the study of energy transformations. The first law of thermodynamics explains that the energy of universe is constant; energy can be transferred and transformed but not created. the second law of thermodynamics is that during every energy transfer or transformation some energy becomes unusable.

What is osmosis ?

Osmosis is the diffusion of water across a selectively permeable membrane. This membrane allows some substance to cross more easily than others. The perfect scenario is when there's perfect balance between the water and solute concentration (when the cell volume is constant) is called isotonic. Hypertonic is when the water goes out of the cell on the other hand hypotonic is when water comes into cell which makes the cell to increase its volume

Diagram :

This diagram shows how the enzyme decreases activation energy to make more reaction happen without being consumed by the reaction .

5facts:

Selectively permeable membrane is important in keeping the cell's volume constant. This membrane manages what substances will go in the cell and which won't.

ATP powers nearly all forms of cellular work.

Exergonic reaction are those that releases energy, endergonic are those which consume energy.

Every working cell in every organism carries out thousands of exergonic and endergonic reactions. The total of an organism's chemical reactions is called metabolism

Exocytosis is a name of process that exports bulky materials such as proteins outside of the cell.

Endocytosis is a transport process that is the opposite to the exocytosis.

Key terms:

Active transport - in this process a cell must expend energy to move a solute against its concentration gradient

Diffusion - the tendency for particles of any kind to spread out evenly in an available space
Passive transport - the diffusion of a substance across a biological membrane

tonicity - term that describes the ability of a solution to cause a cell to gin or loose water

osmoregulation - control of water balance

kinetic energy - the energy of a motion

potential energy - stored energy that possesses as a result of its location or structure

energy - the capacity to perform work

chemical energy - term that refers to the potential energy available for release in a chemical reaction

cellular respiration - chemical process that uses oxygen to convert the chemical energy that the cell can use to perform work

Video :

Enzymes

Summarize :

The chapter name Working cell tells us a lot about this chapter it describes function it performs, effects of enzymes, and all other important things such as the thermodynamic laws and the effects of solute and water concentration .

Chapter 4

Questions:

1. Why do we need microscopes ?

Microscope is very important invention. It increases the ability of our vision because it magnifies very small objects. Due to this characteristic of microscopes we were able to go a step further in discovering the components of life such as cells atoms and even smaller particles. Before microscope we haven't had an idea of what are living organisms composed of.

2. What does the cytoskeleton do ?

Cytoskeleton is network of protein fibers that helps to organize and maintain structure of the cell and its organelles. We have 3 different types of protein fibers: Microfilaments (form a network that helps support the cell shape); Intermediate filaments (serve to reinforce the cell shape and to anchor certain organelles); Microtubules (they enable movement for cell).

3. What are the main differences between prokaryotic and eukaryotic cell ?

Prokaryotic cells are structurally simpler than eukaryotic cells. Prokaryotic cells lack nucleus, they don't have a membrane around surrounding DNA, ribosomes in prokaryotic cells are smaller than in eukaryotic. Eukaryotic cells on the other hand are more complex and those types of cells are the one found in many complex organisms like humans, plants, animals etc....

Eukaryotic cells have various organelles that maintain the functions of cell, for example : Golgi aparatus, ER, Lysosomes, Chloroplast etc....

Diagram :

On the left side of diagram is shown animal cell (prokaryotic cell) on the right is prokaryotic cell. This diagram shows the main differences between those two types of cells. As you can see prokaryotic cell is lacking nucleus and eukaryotic cell has a various number of organelles.

5facts:

Cilia and flagella move when microtubules bend, which enables the movement of cell

Plant's cell chloroplast are very important throughout the process of photosynthesis

Endosymbiosis it's a theory that mitochondria and chloroplasts were formerly small prokaryotes that began living within larger cell.

Many organelles are connected through endomembrane system

We have two types cells that differ in their structures and that is prokaryotic cell and eukaryotic cell

Key terms :

chromosomes - carry genes made out of DNA

cytoplasm - entire region between the nucleus and the plasma membrane

cellular metabolism - many of the chemical activities of cell

organelles - membrane bounded structures perform specific functions in the cell

nucleus - contains most of the cell's DNA and controls the cell's activities by directing protein synthesis

Ribosomes - cellular components that carry out protein synthesis

Mitochondria - organelles that carry out cellular respiration in nearly all eukaryotic cells

Peroxisome - organelle that is not part of the endomembrane system; included in the breakdown of fatty acids

Lysosome - consists of digestive enzymes enclosed in membranous sac; digesting process

Vacuoles - membraneous sac with various functions such as hydrolitic (absorbs water)

Video :

Basic cell structure

Summarize :

This chapter is talking about the cell and it's basic structure. It describes all organelles and their function for example Nucleus is surrounded by porous nuclear envelope, the nucleus contains the DNA that carries the cell's hereditary blueprint. Also it divides the cell's organelles into group by their function and gives us the basic cell structure and types.

Chapter 3

Question :

What are the organic compounds ?

Organic compounds are carbon based molecules. Carbon is able to form 4 bounds at most. So for example methan's structure is CH4. Another characteristic for carbon is that he's able to create large and diverse molecules. Also the chain of carbon atoms in organic molecules is called a carbon skeleton.

What are the characteristic chemical groups of organic compounds ?

These chemical groups are called functional groups. They have affect on the molecules functions.

Among those functional groups are :

Hydroxyl group - consists of -OH group connected to a carbon skeleton

Carbonyl group - consists of >C=O group connected to a carbon skeleton. There are two types of carbonyl group Aldehyde and Ketone

Carboxyl group - this functional group is -COOH

Amino group - NH2

Phosphate group - OPO3

Methyl group - CH3

What are the different types of macromolecules found in our body ?

The names of these group are lipids, proteins, nucleic acid and carbohydrates.

Lipids are very large molecules composed of glycerol and fatty acid tail. By breaking down the lipids a huge amount of energy is released.

Proteins are polymers constructed from amino acid monomers. The connection between proteins is called peptide bond.

Nucleic acids are very information-rich polymers of nucleotides. We know two types of nucleic acids and those are DNA and RNA.

Carbohydrates also known as saccharides or sugars. Sugar is source of fast energy they don't produce as big amount of energy as lipids but they are really fast.

Diagram :

This diagram shows the basic monosaccharide glucose. Glucose is main saccharide that is contained in most of polysaccharides. It's also part of process called photosynthesis. It's really important sugar.

5facts :

Nucleic acids are very important in giving informations and controlling processes inside the cells and molecules as well as throughout the whole body.

Lactose tolerance is is a recent mutation in the human genome that allows us to drink milk and digest the sugar contained in the milk Lactose.

All functional groups differ in a specific way and also have different function and differ in a way they influence other cells.

Anabolic steroids are synthetic variants of the male hormone testosterone. It causes buildup of muscle and bone mass. They can also be used as prescription drugs. On the other hand it's very often abused mainly by athletes who are trying to gain muscle mass.

Denaturation is a process when protein's loose their specific shape and their function as well.It can be cause due to temperature change, pH change and salt concentration. In some cases this process can't be reversed causing a serious damage.

Key terms :

carbon skeleton - chain of carbon atoms in an organic molecule

organic compounds - carbon-based molecules

monomers - building blocks of polymers

macromolecules - gigantic and four main main classes of large biological molecules

hydrophobic - "afraid of water" molecule doesn't dissolve in water

hydrophilic - "loving water" molecule does dissolve in water

steroids - lipids containing for fused rings. Mainly known as anabolic steroids which are often being abused

saturated lipids - lipids which have maximum number of hydrogens

unsaturated lipids - lipids which don't have a maximum number of hydrogens

enzymes - are specialized macromolecules that speed up chemical reactions in cells.

Video :

Organic compounds

Summarize :

Chapter 3 introduced to us the main compounds, which are carbohydrates, proteins, nucleic acids and lipids. Also it described functional groups and how each of them can completely change function of carbon molecule.

Chapter 2

Questions :

1. What are the main chemical elements found in body?

First. What is the element? Element is a substance that cannot be broken down to other substances by ordinary chemical means. C,O,H,N - Carbon, Oxygen, Hydrogen, Nitrogen. These are four main elements in our body that form most of the body's compounds, such as: proteins, lipids and etc.... There are as well other elements in our body necessary for our body's functions but because they're in so small amounts we call them trace element, such as Ca, P, K, etc....

2. Why are atoms so important for us?

Atom is the smallest unit of matter that still retains the properties of an element. Atom consists of Nucleus which contains Protons and Neutrons and around the nucleus is Electron cloud. Electrons weight 2000 x less than Neutrons and Protons. But the reason why they are so important is obvious everything living is made up of atoms.

3. What is the difference between covalent and ionic bonds?

Ionic bonds form when the attraction of two ions (ion= atom or molecule with an electrical charge resulting from gain or loss of one or more electrons) holds them together.

Covalent bonds form when 2 atoms or molecules share one or more pairs of outer-shell electrons. So ionic bonds are formed by attraction 2 molecules but covalent bonds are when the molecules share their outer-shell electrons.

Diagram :

Diagram explains the way covalent bonds are created. Molecules connected by a covalent bond share their outer shell electrons to have their outer shell completely full. You can see that H has one non pair outer shell electron but when they connected the free electrons are now in the same shell connected.

5facts :

Elements are rarely found in their pure form. Elements usually form compounds which is a substance consisting of two different elements combined in a fix ratio.

Atoms are the smallest units of matter. They are the basic "building structures" throughout our bodies. They can be also radioactive that happens when they release energy and particles.

Radioactive isotopes can be very helpful. We use them to discover certain types of diseases and also they help us date archeological findings.

Chemical reaction make bonds and break them. Those changes lead to change in a composition of matter. Chemical reactions are obtaining most of the basic functions in our which means that if all chemical reactions would stop our body would stop too.

Hydrogen bonds are very specific for water due to these bonds water have different properties than it'd normally have without them. For example the water doesn't completely freeze in oceans which secures the survival of animals living in water.

Key terms :

pH scale - describes how acidic or basic a solution is. Our blood's pH is 7.4

acid - acidic solution have bigger amount of H+ than neutral solution

base - basic solution contains more OH- ions than neutral solution

solvent and solute - the dissolving agent is the solvent and the substance being dissolved is solute

element - substance that can't be broken down to other substances by ordinary chemical means

matter - everything is composed of matter, which is anything that occupies space and has mass

trace elements - elements found in body that are essential but are in a minute quantities

compound - substance consisting of two or more elements combined in fixed ratio

ion - is an atom or molecule with an electrical charge resulting from a gain or loss of one or more electrons

chemical bond - is when two atoms complete their outer shell

Video:

Covalent bond

Summarize :

Chapter 2 describes elements, atoms and molecules. Also the difference between chemical bonds and their characteristics. Also a big part of this chapter talked about water and its specific characteristic such as: cohesion and adhesion, hydrogen bonds (very typical for water) and etc.... It also described pH scale and what this scale represents.