Biochemistry: Introduction to Biochemistry

Biochemistry

From the word bio and chemistry: life and how things interact

Biochemistry

The branch of science in which you study the chemical and physical processes that occur in an organism

Biochemistry

Emerged as a distinct discipline around the beginning of the 20th century when scientists combined chemistry, physiology, and biology to investigate the chemistry of living systems by:

• Studying the structure and behavior of complex molecules found in biological material

• The way these molecules interact to form cells, tissues, and whole organism

Principles of Biochemistry

Cells (basic structural units of living organisms) are highly organized and constant source of energy is required to maintain the ordered state.

Principles of Biochemistry

Living processes contain thousands of chemical reactions. Precise regulation and integration of these reactions are required to maintain life.

Principles of Biochemistry

Certain important reaction (e.g. glycolysis) is found in almost all organisms

Principles of Biochemistry

All organisms use the same type of molecule: Carbon Hydrogen and Oxygen (building blocks of organic molecules), proteins, lipids, and nucleic acids. However, carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorous are the common elements making up a living system.

Principles of Biochemistry

Instruction for growth, reproduction, and development for each organism is already encoded in their DNA.

Cells

Basic building blocks of life

Cells

Smallest living unit of an organism that is capable of performing metabolic/biomolecular processes.

Cells

Grow, reproduce, use energy, adapt, respond to their environment

Cells

Many cannot be seen with the naked eye (microscopic)

Cells

Can be unicellular (e.g. prokaryotes; bacteria) and multicellular organisms [e.g. eukaryotes, fungi, yeast, and Kingdom Prostita (protists)].

Cells

Organization of human body: Chemical Level > Cells > Tissues > Organs > Organ Systems > Organism

microscopic

too small to be seen except under a microscope

macroscopic

visible to the naked eye

micrometer

1/1000 millimeter

Largest cell

ostrich egg (18cm)

Smallest cell

Mycoplasma (1 μm)

Mycoplasma

genus of bacteria that lacks cell wall around their cell membrane

Smallest cell in the human body

sperm cell (5 μm)

largest cell in the human body

Egg Cell (120μm)

Longest cell in the human body

Nerve Cell (1 meter)

Shape of Cells

Shape dictates function

Cells that can change shape:

Euglena and Amoeba

Human Red Blood Cells

o Circular biconcave (donut shape)

o For easy passage through human capillaries

Nerve cells

o Branched

o to conduct impulses from one point to another

Human white blood cells

o Can change their shape to engulf microorganisms that enter the body

Nuclear pore

- Embedded in the nuclear envelope

- Passage of material into or out of the nucleus

Nucleus

- Control or command center of the cell

- Regulates all activities in the cell

- All activities are encoded in the nucleus through the production of proteins

Nuclear Envelope

- Discriminates the content of the nucleus from the external or cytoplasmic environment

Rough Endoplasmic Reticulum

- Used for protein synthesis

Mitochondrion

- Powerhouse of the cell

- ATP is synthesized

- Cellular respiration takes place (Krebs Cycle and Electron Transport Chain)

Cytoplasm

- Refers to the fluid portion of the cell

- Where organelles embedded

Microfilaments

- Adds structural integrity to the cell

- Acts as the cable network that transports material in the cell form one point to another

e.g. RER > Golgi Apparatus

Golgi Apparatus

- Part of the endomembrane system

- Plays an integral role in synthesizing proteins

- Packages and modifies the proteins

Cilia

- Filters microscopic particles

- Line of defense for the body

Lysosome

- Suicide bag of the cells

- Contains the digestive enzymes

- Engulfs foreign invaders

Centriole

- Plays a role in cell division - Manufacturing sight for microtubules

Microtubules

- Have the ability to polymerize or depolymerize (shorten or lengthen)

- Plays a role during cell division

- Separates sister chromatids during the Anaphase in cell division

Plasma Membrane

- Semi permeable membrane

o Selectively; allows certain molecules to enter or exit the

cell

- Has two layers of phospholipids

Smooth Endoplasmic Reticulum

- Used in lipid synthesis

Ribosomes

- Sight of protein synthesis

- Translation of mRNA from the nucleus

- Where decoding of amino acid happens

Nucleolus

- Where ribosomal RNA is synthesized (main component for ribosomes)

Free ribosomes

- For protein synthesis

three features in almost every cell:

1. plasma membrane

2. nucleus (eukaryotic cells)

3. cytoplasm.

plasma membrane

Extremely delicate, thin, elastic, living and semipermeable membrane (semi-permeable because it allows the entry of certain molecules)

plasma membrane

Made up of two layers of lipid molecules in which protein molecules are floating; includes the presence of proteins (transporters), glycoproteins and glycolipids.

plasma membrane

Thickness varies from 75 - 110 A° (angstrom)

plasma membrane

Can be observed under an electron microscope only

Plastids

Often contain different types of pigments that can change the color of the cell

Chromoplasts

Contains pigments namely in flowering plants

Leucoplasts

Contains food (elaioplast, amyloplast, proteoplast)

Chloroplast

Contains the green pigment (chlorophyll)

Chloroplast

Double membrane-bound organelles found mainly in plant cells

Chloroplast

Usually spherical or discoidal in shape

Chloroplast

Shows two distinct regionsgrana and stroma

Grana

are stacks of thylakoids (membranebound, flattened discs)

Thylakoids

contain chlorophyll molecules which are responsible for photosynthesis.

Stroma

is a colorless dense fluid

Centrosome

It is the membrane bound organelle present near the nucleus

Centrosome

Consists of two structures called centrioles

Centrioles

Are hollow, cylindrical structures made of microtubules

Centrioles

Arranged at right angles to each other

Cytoskeleton

microfilament

Cytoskeleton

Microtubules are hollow tubules made up of protein called tubulin

Cytoskeleton

Microfilament are rod shaped thin filaments made up of protein called actin

Two Main Types of Eukaryotic Cells:

• Animal Cell

• Plant Cell

prokaryotic cell

1. Nucleus is undeveloped

prokaryotic cell

2. Only one chromosome is present

prokaryotic cell

3. Membrane bound organelles are absent (lack complexity)

prokaryotic cell

4. Size ranges from 0.5-5 μm

prokaryotic cell

5. Examples: bacteria, and blue-green algae

Eukaryotic cells

1. Nucleus is well developed

Eukaryotic cells

2. More than one chromosome is present

Eukaryotic cells

3. Membrane bound organelles are present (complex)

Eukaryotic cells

4. Size ranges from 5-100 μm

Eukaryotic cells

5. Examples: all other organism (anima cell, plant, cell, fungi, and protist)

cell wall

Non-living and outermost covering of a cell (plants, fungi, and bacteria)

cell wall

Can be tough, rigid and sometimes flexible

cell wall

Made up of different polysaccharides: cellulose, hemicellulose, and pectin.

cell wall

May be thin or thick, multilayered structure

cell wall

Thickness varies from 50-1000 A°(angstrom)

Nucleus

Dense spherical body located near the center of the cell

Nucleus

- Diameter varies from 10 to 25 μm (micrometer)

Nucleus

Present in all the cell except red blood cells and sieve tube cells

Nucleus

- Well developed in plant and animal cells

Nucleus

- Undeveloped in bacteria and blue-green algae (cyanobacteria)

Nucleus

- Most of the cells are uninucleated (having only one nucleus)

Nucleus

- Few types of cells have more than one nucleus (skeletal muscle cells)

Components of Nucleus

NuNuFiGeCh (Nuclear membrane, Nucleoplasm, Fibres, Genes, Chromosomes)

Nuclear Membrane

- Double layer covering of nucleus

- Has pores of diameter about 80-100 nm

Nucleoplasm

- Colorless dense sap present inside the nucleus

- Contains round shaped nucleolus and network chromatin fibres

Fibres

- Composed of deoxyribonucleic acid (DNA) and protein histone

- Are condense to form chromosomes during cell division

Chromosome

- Contain stretches of DNA called genes

Genes

- Transfer the hereditary information from one generation to the next

Cytoplasm

Jelly-like material formed by 80% of water

Cytoplasm

Present between the plasma

Cytoplasm

Contains a clear liquid portion called cytosol and various particle

Cytoplasm

Particles are proteins, carbohydrates, nucleic acids, lipids and inorganic ions