CHAPTER 3 CELL PROCESSES

Chemistry of life Everything around you is made up of matter and energy. Matter- anything that takes up space Energy- can hold matter or break it apart Matter is made of atoms -Its nucleus contains protons and neutrons -Outside the nucleus are electrons, which are involved in a chemical reaction

Elements- made up of only one type of atom -They cannot be broken down into simpler forms by ordinary chemical reactions. -Arranged in a chart called the periodic table of elements COMPOUNDS- molecular and ionic -Made of two or more elements in exact proportions -Have different properties from the element they are made of -The smallest part of a molecular compound is called a molecule * A molecule is a group of atoms held together by the energy of chemical bonds. They form when atoms share electrons.

Ionic compound- -Ions- electrically charged atoms, positive or negative -Ions of opposite charges attract one another to form electrically neutral compounds MIXTURE- combination of substances in which individual substances keep their own properties. Solution- mixture in which two or more substances are mixed evenly. Suspension- forms when a liquid or gas has another substance evenly spread throughout it

ORGANIC COMPOUNDS -Contains carbon and hydrogen and are usually associated with living things or things that were once alive; four groups of organic substances make up all living things. 1.Carbohydrates-supply energy for cell processes 2.Lipids- store and release large amounts of energy 3.Proteins- the building blocks of many structures - amino acids- smaller molecules that make up proteins -enzymes- proteins that regulate all activities in the cell 4. Nucleic Acids- store important coded information in cells

INORGANIC COMPOUNDS Usually made from elements other then carbon THE IMPORTANCE OF WATER -Living things are composed of more then 50% of water and depend on it to survive. -All chemical reactions in living things take place in water solutions - Most living things use water to transport materials throughout their bodies/

What are we made of? Organic compounds, including carbohydrates, lipids, proteins and nucleic acids. Also inorganic compounds, like water. On a smaller level, these compounds are made of elements, which are made of atoms

Moving molecular material Cells have a selectively permeable membrane that regulates what goes into and out of the cell. PASSIVE TRANSPORT- the movement of substances through a cell membrane without the input of energy Diffusion- when molecules move away fromarea where there are more of them into areas where there is fewer of them; stops when the molecules of one substance are spread evenly throughout another substance, and EQUILLIBRIUM occurs.

Osmosis- the diffusion of water through a cell membrane In Fascilitated diffusion-transport proteins move substances into or and out of the cell. Active Transport- Requires energy to move a substance through a cell membrane

ENDOCYTOSIS AND EXOCYTOSIS -endocytosis- the process in which a substance is taken into a cell by surrounding it with the cell membrane, form in a sphere called a vesicle. -exocytosis- the process in which the membrane of the vesicle fuses with the cell membrane and the vesicle’s contents are released outside the cell.

What need’s to be transported in your body? Nutrients form food, and water needs to be transported into a cell; wastes and carbon dioxide need to be transported out of a cell.

ENERGY FOR LIFE Cells use chemical reactions to change the chemical energy stored in food into forms needed to perform activities Metabolism- the total chemical reactions in sn organism - The chemical reactions of metabolism require enzymes

Photosynthesis The process that plants and other organisms use to convert light energy into chemical energy or sugars to be used as food. -Producers- organisms that make their own food -Consumers- organisms that cant make their own food * Cholorophyll and other pigments are Used in photosynthesis to capture light Energy which is used to produce sugar And oxygen.

Respiration The process in which chemical reactions break down food molecules into simpler substances and released stored energy. 1.Respiration of carbohydrates begins in the cytoplasm -Carbohydrates are broken down into glucose molecules -Each glucose molecule is broken down into two simpler molecules, releasing energy. 2. Respiration moves into the mitochondria -The two simpler molecules are broken down again, releasing much more energy -the process uses oxygen and produces CO2 and water as wastes.

Fermentation FERMENTATION Cells that do not have enough oxygen for respiration use this process to release some of the stored energy in glucose molecules. -entire process occurs in the cytoplasm -Produces lactic acid, alcohol, and carbon dioxide as wastes

Photosynthesis and respiration THE OPPOSITE OF EACH OTHER -Photosynthesis produces sugars and oxygen, which are used in respiration -respiration produces carbon dioxide and water, which are used in photosynthesis

Cell reproduction Cell division- Increases the number of cells that may cause many celled organisms to grow. The cell cycle -The cells have periods of formation, growth and development, and death called life cycles. -Interphase- most of life in any eukaryotic cell, or cell with a nucleus, is spent in a period of growth and development -During interphase, a cell duplicates its chromosomes and prepares for cell division -After interphase, the nucleus divides, and the cytoplasm seperates to form two new cells

MITOSIS Process in which the nucleus divides to form two new nuclei 1. Chromosome- structure in the nucleus that contains hereditary material 2. Prophase -the nucleolus and nuclear membrane disintergrate - centrioles move to opposite ends of the cell Spindle fibers begin to stretch across the cell

Metaphase -Pairs of chromatids line up accross the center of the cell. Anaphase -each centromere divides - Each pair of chromatids separates and moves to opposite ends of the cell

Telophase -Spindle fibers disappear and a new nucleus forms. Division of the cytoplasm- for most cells the cytoplasm separates after the nucleus divides - In animal cells, the cell membrane pinches in the middle and the cytoplasm divides. -In plant cells, a cell plate forms

mitosis

Results of Mitosis Each cell in your body, except sex cells, has a nucleus with 46 chromosomes Allows growth and replaces worn out or damaged cells. Asexual Reproduction -An organism with no nucleus divides into two identical organisms by fission. -Budding- a small exact copy of the adult grows from the body of the parent -Regeneration- a whole new organism grows from each piece of the parent

FISSIONBUDDING REGENERATION

SEXUAL REPRODUCTION AND MEIOSIS Sexual reproduction- two sex cells, usually an egg and a sperm, come together. Fertilization- the joining of an egg and a sperm, generally from two different organisms of the same species.

Sperm are formed in the male reproductive organs. Eggs are formed in the female reproductive organs. A zygote forms from fertilization of a sperm and egg. Following fertilization, cell division begins and a new organism develops. Human body cells are DIPLOID because they contain 23 PAIRS of similar chromosomes. Human sex cells are HAPLOID because they have 23 SINGLE chromosomes’

MEIOSIS A process that produces haploid sex cells and ensures that offspring have the same diploid number as its parent. 1. In meiosis1, the nucleus divides and produces 2 new cells with one duplicated chromosome each. 2. In Meiosis 2, the nuclei divide and the chromatid separate, producing 4 cells with half the number of chromosomes of the original nucleus.

DNA A chemical that contains information that an organism needs to grow and function Watson and Crick developed an accurate model of DNA in 1953

The structure of DNA is similar to a twisted ladder. -The sides of the ladder are made up of sugar phosphate molecules -The rungs of the ladder are made up of nitrogen bases

Before a cell divides, its DNA duplicates itself by unwinding and separating its sides, then each side becomes a pattern which a new side forms

GENES- section of DNA on a chromosome Contain instructions for making specific proteins RNA carries the codes for making proteins from the nucleus to the ribosomes in the cytoplasm. -Messenger RNA carries the code that directs the order in which the amino acids bond -Ribosomal RNA makes up the ribosomes, where proteins are built -Transfer RNA bring amino acids to the ribosomes to build the protein. Cells use only the genes that direct the making of proteins needed by that cell.

MUTATIONS Any permanent change in the DNA sewuence of a cell’s gene or chromosome -Can be caused by outside factors like x-rays, sunlight, and chemicals. -A change in a gene or chromosome can change the traits of an organism

Some examples of mutations