10 Natural Science - The Chemistry of Life

cell theory, osmosis, mitosis

hypertonic

A higher concentration of solutes

hypotonic

A lower concentration of solutes

isotonic

An equal concentration of solutes

Inorganic compounds

Make up non-living things, make up many essential substances such as water, hydrogen and carbon

Organic compounds

make up living things, contain carbon bound to hydrogen, elements arranged into large, complex chemical compounds which consist of monomers bound together to form polymers

Carbohydrates

serve as fuel and building material, consist of C, H, and O (H to O ratio is 2:1)

Lipids

contain C, H, and O, but in different ratios, rich energy source but difficult to digest, insoluble, long chains of fatty acid molecules and glycerol units

Nucleic acids

The subunit is the nucleotide (consists of sugar, phosphate, and nitrogenous base), they provide genetic instructions that code for proteins

proteins

Contain C, H, O as well as N, P, S, and other elements, Each molecule is a long chain of amino acid units (20 or so various kinds), can be denatured by heat, strong acids, ad bases

Monosaccharide

Simple sugars, are soluble and used in respiration, e.g., glucose

Disaccharide

Complex sugars, consist of two saccharide units bonded together, e.g., lactose

Polysaccharide

Long chains of sugar units, are insoluble and used for energy storage (e.g. glycogen and starch) and structural purposes (e.g. cellulose and chitin)

Carbohydrate examples

Sugar, celery, pasta

Lipid examples

Waxes (e.g., plant cuticles), Steroids (e.g., sex hormones), Pigments (e.g., chlorophyll), Phospholipids (e.g., cell membranes)

Nucleic acid examples

deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)

Protein examples

Enzymes, Hormones, Important blood proteins, Structural materials, Pigments

Monomers

Small molecules and building blocks for polymers

Polymers

Large molecules, made out of bonded monomers

Hydrolysis

The breaking down of polymers into monomers

Condensation

The bonding of monomers together to form polymers

Catalyst

A substance that speeds up a chemical reaction without being changed

Enzyme

A biological catalyst (usually a protein)

Substrate

The reactant molecules that an enzymes works on

Active site

The part of the enzyme where the substrate binds

Denature

Process of permanently modifying the structure of a protein (enzyme)

Factors affecting enzymes

there are many things that can affect the activity if enzymes, two of which are temperature and pH

Enzyme shape

the shape of enzymes is very important, the active site is extremely specific to the substrate that is acted on, this means that anything that causes the enzyme to change shape (denature) will stop it from working

Eukaryote cell

Has membrane bound organelles, multicellular, big, has a nucleus

Prokaryote cell

Doesn’t have membrane bound organelles, unicellular, small, doesn’t have a nucleus

Animal cell

Have centrioles, lysosomes, flagella

Plant cell

Have cell wall, chloroplasts, chlorophyll, large vacuoles

Cell/plasma membrane

helps to protect the cell, maintain their shape and keeps the cell from absorbing too much water, animal cells have an extracellular matrix that helps hold the cells together in tissues and protects and supports them

Cell wall

Only in plants, protects the insides and makes the cells rigid

Nucleus

Contains the cell’s DNA, the largest of all organelles, genes in the nucleus carry information necessary to make proteins, the nucleus is bordered by a double membrane called the nuclear envelope

rough endoplasmic reticulum

Synthesises an enormous variety of molecules, Then packages the molecules into transport vesicles, Rough due to ribosomes on the outer membrane, Ribosomes synthesis proteins

smooth endoplasmic reticulum

used for detoxification and makes some lipids, e.g., steroids

Golgi apparatus

Works in partnership with the endoplasmic reticulum, Refines, stores, and distributes the chemical products produced in the ER

Lysosome

A membrane enclosed sac, Contains digestive enzymes, Has three main functions: Fuse with food vacuoles to digest the food, Break down damaged organelles, Help destroy harmful bacteria

Vacuole

Membranous sacs used for storage (mostly in plants), Animals only have a few small vacuoles

Chloroplast

Only found in plants and algae, Sites of photosynthesis, Convert light energy to chemical energy

Mitochondria

The powerhouse of the cell, Sites of cellular respiration, Use glucose and oxygen to produce chemical energy (ATP), Found in all eukaryotic cells, CO2 + H2O -\> C6H12O6+O2+H2O

Cytoskeleton

Not a true organelle, Network of fibres that Provide mechanical support and allow cells to change shape and move, Assist on cell division

Cilia and flagella

Are motile appendages, flagella propel the cell in a whiplike motion, Cilia move in a coordinated back-and-forth motion

Selective permeability

a property of cell membranes, membranes are said to be semipermeable., i.e., they allow certain molecules or ions to pass through.

Osmosis

the overall (net) movement of water molecules from a dilute solution to a more concentrated solution through a semi-permeable membrane.

Concentration gradient

The difference in concentration of molecules across a space

Limitations to cell size

A cell needs to be able to take in nutrients and eliminate wastes effectively. Since this mainly occurs via diffusion, factors that affect the diffusion will also affect a cells ability to survive

Chromatid

One of two duplicated chromosomes connected at the centromere

Centromere

Region of chromosome where microtubules attach during mitosis and meiosis

Cell cycle

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Mitosis

a part of the cell cycle process by which chromosomes in a cell nucleus are separated into two identical sets of chromosomes, each in its own nucleus (diploid cells), a cell splits to create two identical copies of the original cell -\> asexual reproduction

Interphase

The cell at rest, Accounts for 90% of the cycle, During interphase, the cell grows and copies its chromosomes in preparation for cell division

Prophase

Chromatin condenses into chromosomes, Nucleoli disappears, Each duplicated chromosome appears as two identical sister chromatids, joined at the centromere, Mitotic spindle begins to form, Centrosomes move to opposite ends of the cell, Nuclear envelope fragments, Microtubules extend from each centrosome and attach to the centromeres of the chromosomes

Metaphase

Longest state of mitosis, Centrosomes are at opposite ends of the cell, Chromosomes line up along the metaphase plate, an imaginary plane in the middle of the cell, Each sister chromatid is attached to a microtubule from the opposite side of the cell

Anaphase

Shortest stage of mitosis, Sister chromatids separate, each becoming a full-fledged chromosome, The chromosomes are then pulled to opposite ends of the cell, The cell elongates

Telophase

Two daughter nuclei begin to form in the cell, Chromosomes are decondensing, Cytokinesis is underway

cancer

begins when genes controlling cell growth and multiplication become mutated by carcinogens, One example is the p53 gene, which normally acts to prevent cell division in damaged cells

Rate of diffusion

Temperature – higher temp -\> faster diffusion, Surface area – larger area -\> faster diffusion, Concentration gradient – higher gradient -\> faster diffusion, Size of particles – smaller particles -\> faster diffusion, Diffusion medium – solid \= slowest, liquid \= faster, gas \= fastest

Cell reproduction

Cell replication is a normal part of maintaining a healthy body, Growth, inheritance, and reproduction depend on cell division, Prokaryotic cells divide by binary fission, Eukaryotic cells divide by mitosis and meiosis

Chromosome replication

Before a cell can divide it must copy all of its chromosomes, Copied chromosomes remain joined and are called sister chromatids, Usually, chromosomes appear as chromatin but during cell division they become condensed packages so that they can be moved around easily, 46 chromosomes in each human cell

simple diffusion

Movement of solutes across the cell membrane with the concentration gradient between the phospholipid molecules.

facilitated diffusion

Movement of solutes across the cell membrane with the concentration gradient through the carrier proteins

osmosis

Movement of solvent (water) across the cell membrane with the concentration gradient between the phospholipid molecules and via aquaporins (protein channels)

ion pumps

Movements of substances against the concentration gradient through the carrier proteins

endocytosis

Bulk transport of liquids (pinocytosis) or solids (phagocytosis) into the cell

exocytosis

Bulk transport of substances out of the cell