biology DP year 1

simple diffusion

the process where molecules move from an area of high concentration to an area of low concentration until they reach an equilibrium

facilitated diffusion

uses transport proteins to help molecules cross

channel proteins

create channels for specific molecules/ions

carrier proteins

change shape to move molecules across membrane

passive transport

requires no energy and includes simple diffusion, facilitated diffusion, and osmosis

active transport

requires energy (ATP) and helps bring in nutrients, expel waste and directly pump molecules against their concentration gradient.

osmosis

diffusion of water molecules across a selectively permeable membrane

characteristics of membranes

selectively permeable which allows specific molecules to pass through and transport proteins assist in molecular movement

protein composition

is primarily made up of amino acids linked by peptide bonds, forming polypeptides that fold into functional structures.

what do amino acids contain?

contain an amino group, a carboxyl group, a hydrogen atom, and an R-group that varies for each amino acid.

non-polar hydrophobic R-groups

they include carbon and hydrogen atoms

polar and hydrophilic R-groups

they include oxygen, sulfur, or nitrogen which has a high electronegativity

the 4 protein structure levels

primary, secondary, tertiary, and quaternary structure levels.

primary structure

a unique string of amino acids

secondary structure

the folded or coiled structures that form within a protein due to hydrogen bonding between amino acids, commonly seen as alpha helix and beta pleated shapes.

tertiary structure

forms a polypeptide into a three-dimensional shape that is stabilized by various interactions, including hydrophobic interactions, ionic bonds, and disulfide bridges

quaternary structure

the arrangement of multiple polypeptide chains into a single functional protein complex.

two main protein categories

are fibrous proteins and globular proteins

fibrous proteins

are elongated and insoluble proteins that provide structural support and strength, commonly found in keratin and collagen (nails, hair, connective tissue)

globular proteins

are spherical and soluble proteins that form complex shapes, often found in hemoglobin and insulin.

conjugated proteins

proteins that contain one or more non-polypeptide subunits in addition to their polypeptides, such as hemoglobin which contains 4 polypeptides and 1 iron atom

non-conjugated proteins

does not contain minerals to cause a functional change, such as insulin

cohesion

water molecules that stick to other molecules via hydrogen bonding

water movement through plants

the pulling forces caused by the evaporation of water from leaves makes water move upwards against gravity as an intact water column through the xylem tubes in plants

surface tension

caused by the attraction of water to each other which doesn’t easily want to bond with oxygen

adhesion

the attraction between the polar ends of molecules and polar surfaces, such as membranes, containers, spiderwebs, cellulose, and fibers in xylem vessels

capillary action

the process of a liquid flowing in a narrow space without the assistance of external forces like gravity.

 𝛼 glucose

the hydroxyl group that isn’t on the same plane as the CH₂OH

𝛽 glucose

the hydroxyl group that is on the same plane as the CH₂OH

carbohydrates as short-term energy storage

glucose

carbohydrates as long-term energy storage

stored in complex carbohydrate structures such as starch and glycogen

cellulose

form cell walls and the main plant structure

chitin

a shrimp’s flexible casing and the hard parts of insects

glycoproteins

form markers on cell membranes for recognition

glycolipids

helps cell to cell recognition

composition of polysaccharides, disaccharides, and monosaccharides

composed of carbon, hydrogen, and oxygen with the ratio of C:H:O is 1:2:1

disaccharides

formed when two monosaccharide monomers join together through a glycosidic bond during a condensation reaction

polysaccharides

consists of many monosaccharides linked together such as starch, glycogen, and cellulose.

composition of starch

amylose (straight with no branches) and amylopectin (branching)

polysaccharides as energy in plant cells

the hydrogen bonding of amylose causes it to form a secondary structure through 𝛼 1-4 glycosidic bonds as well as 𝛼 1-6 glycosidic bonds in amylopectin to form branched chains.

polysaccharides as energy in animal and fungi cells

glycogen serves as energy storage for animals and is made of more 𝛼 1-6 glycosidic bonds which is more complex because of the higher number of branches

polysaccharides as a structural component in plant cells

cellulose is made by linking 𝛽 1-4 glucose bonds forming a straight chain

glycoproteins

plays a role in cell-to-cell recognition because they are attached to the cell membrane

Enzymes are…

protein catalysts in living things that speed up biological reactions without being changed

Compositions of enzymes

they are composed of globular proteins with polypeptides that fold into three-dimensional shapes.

Model used to describe how enzymes work

Lock and key or induced fit model

Process of enzyme-substrate complex

bind through an active site which creates the enzyme-substrate complex. This process helps facilitate both anabolic and catabolic processes.

The two types of enzyme inhibition

competitive inhibition and non-competitive inhibition

the effect of inhibitors

inhibitors reduce enzyme activity by binding to the enzyme which prevents or slows down the enzymatic reactions

non-competitive inhibitors

bind to the allosteric site on the enzyme which makes a conformational change slowing down or preventing the substrate from bonding. This happens regardless of the substrate concentration.

two factors affecting enzyme activity

temperature and pH levels which cause denatured enzymes

the two metabolic processes

catabolism and anabolism

catabolism

the metabolic process that breaks down molecules to produce energy.

anabolism

the metabolic process of building up larger molecules from smaller ones which requires energy.

renin

used in the food industry to help curdle milk and make cheese.

pectinase

used in the food industry to break down pectin in fruits and vegetables, helping in juice clarification.

proteases

used in cosmetics to break down proteins, helping with skin exfoliation.

cellulase

used in paper production to break down cellulose, improving pulp processing.

polymerase

used in genetics to synthesize DNA and RNA, playing a crucial role in DNA replication and transcription.

lipases

used in detergents to break down fats and oils, enhancing cleaning efficiency.

lactase

used in the food industry to break down lactose into glucose and galactose, aiding lactose digestion.

examples of monomers

simple carbohydrates (mono- or di- saccharides), amino acids, fatty acids and glycerol, and nucleotides

examples of polymers

complex carbohydrates (polysaccharides), proteins, lipids, and nucleic acids (DNA, RNA)

simple carbohydrates (mono- or di- saccharides)

complex carbohydrates (polysaccharides)

amino acids

proteins

fatty acids and glycerol

lipids

nucleotides

nucleic acids (DNA, RNA)

dehydration synthesis

the process of creating polymers by removing water from monomers

hydrolysis

breaking down polymers into monomers by adding water by separating hydrogen and hydroxyl

Water potential

The potential of energy of water molecules to move across a semi-permeable membrane

Formula for water potential

Total = solute + pressure

Net movement of water

Moves from high concentration to low concentration

Isotonic

Balanced solution with equal concentration on both sides of the membrane

Hypertonic

Higher solute concentration where water moves out of the cell

Hypotonic

Lower solute concentration where water moves into the cell

Animal cells in hypotonic solutions

Water enters the cell which causes the cell to swell and therefore burst due to lack of cell wall

Animal cells in isotonic solutions

Ideal solution for the cell

Animal cells in hypertonic solutions

Water moves out of the cell causing it to shrivel and become unhealthy

Plant cells in hypotonic solutions

Becomes turgid which is ideal for a plant cell

Plant cells in hypertonic solutions

The plant cell experiences plasmolysis which causes the cell membrane to shrivel away from the cell wall

Plant cells in isotonic solutions

This causes the plant to become droopy

Osmosis

The passive movement of water across a semi-permeable membrane

Water movement changes by

Solute concentration, membrane permeability, and pressure differences

Cohesion

Water molecules attracted to each other

Hydrogen bonding

Critical in water molecule interactions

Solvent polarity

Determines how substances dissolve

amphipathic

having both a hydrophilic region and a hydrophobic region

cholesterol

a steroid that forms an essential component of animal cell membranes

davson-danielli model

a model of cell membranes in which a phospholipid bilayer is covered in a layer of protein

fluid mozaic model

a model of cell membranes in which proteins are embedded in a phospholipid bilayer

glycoprotein

a protein with one or more carbohydrates attached

hydrophilic

“water-loving” ; polar molecules that are soluble in water

hydrophobic

“water-fearing” ; nonpolar molecules that do not dissolve in water

permeability

the ability of membrane to let things in and out

phospholipid

a lipid with a phosphate group in its hydrophilic head. The main constituent of cell membranes.

phospholipid bilayer

a double layer of phospholipids that makes up cell membranes

viruses can

exchange genetic material with their host cells which means that viruses can adapt and evolve rapidly to new environments.

viruses can also be used for

treating diseases and the development of new vaccines

how small are viruses

they are small infectious particle that can range from 20nm to 500nm

all viruses contain

either RNA or DNA as their genetic material, a capsid, and no cytoplasm or plasma membrane