GCSE- A-Level headstart Flashcards
proteins
What are proteins made of?
generally
long chains of amino acids
proteins
How many different amino acids are used in proteins?
20
proteins
what elements do all proteins contain?
what do some contain?
Carbon, Hydrogen, Oxygen, Nitrogen
sulfur
proteins
What are proteins held together by?
the amino acids in a protein chain are attached by strong peptide bonds
proteins
How can amino acids be arranged
how many amino acids can make a protein
in any sequence
up to several hundred amino acids
proteins
what decides the structure and function of a protein
the order of amino acids in a protein decides its structure which decides its function
proteins
what is the primary structure of a protein
the order in which amino acidsare arranged in a protein chain
proteins
What is the secondary structure of a protein
when chains coil up or fold into pleats that are held together by weak forces of attraction called hydrogen bonds. The coils and pleats are the secondary structure
proteins
what is the tertiary structure of proteins
The coiled chain of amino acids is folded into a ball thats held together by a mixture of weak chemical bonds (hydrogen) and stronger bonds (disulfide)
proteins
what is a globular protein
when the protein has a roughly spherical shape
carbohydrates
What 3 elements do carbohydrates contain
carbon, hydrogen, oxygen
carbohydrates
examples of the several types of carbohydrates
sugars, starch, cellulose
carbohydrates
what are sugars?
physically
small water-soluble molecules that taste sweet
carbohydrates
what two groups are carbohydrates divided into
monosaccharides
disaccharides
carbohydrates
what are monosaccharides
the single units from which all other carbohydrates are built
glucose and fructose are both types of monosaccharides
carbohydrates
when are disaccharides formed
what is also formed
when 2 monosaccharides are joined by a chemical reaction
water since it is a condensation reaction
carbohydrates
glucose+glucose–>
maltose+ water
maltose= disaccharide
carbohydrates
glucose+fructose–>
sucrose+ water
sucrose= disaccharide
carbohydrates
what is a polysaccharide
example?
a polymer (long chain molecules created by repeating units of monomers- in this case monosaccharides)
an example= starch, cellulose
carbohydrates
which 2 different polysaccharides is starch made up of?
amylose
amylopectin
both are polymers of glucose
carbohydrates
what is cellulose
a polymer of glucose where the molecules are bonded weakly by hydrogen bonds making cellulose molecules long and straight
carbohydrates
what are microfibrils
created when several cellulose molecules lie side by side, they strengthen plant cell walls
carbohydrates
where is cellulose found
only in plant cells
lipids
what 3 elements do lipids contain
carbon, hydrogen, oxygen
lipids
what are lipids
generally
oils and fats
lipids
what are plant oils and fats made of
a group of lipids called triglycerides
lipids
what is a triglyceride made up of
a molecule of glycerol with 3 fatty acids attached to it
lipids
what is a fatty acid molecule
a long chain of carbon atoms with an acid group (-COOH) at one end.
hydrogen atoms are attached to the carbon atoms
lipids
what is a saturated fatty acid
if every carbon atom n the chain is joined by a single bond
lipids
what is an unsaturated fatty acid
if one or more of the bonds in the chain of carbon atoms is a double bond
a fatty acid with many double bonds is polyunsaturated
lipids
what are phospholipids
they are like triglycerides but instead of having 3 fatty acid chains they have 2 fatty acid chains and a phosphate group
cell membranes are made from a double layer of phospholipids
enzymes
what is metabolism
the sum of thousands of biochemical reactions that take place every second in a living cell
enzymes
what is a metabolic pathway
a single chain of biochemical reactions
enzymes
what are enzymes
they are biological catalysts which increase the rate of reactions
enzymes
what is activation energy
what do enzymes do to activation energy
the minimum amount of energy required to start a chemical reaction
they reduce the amount of activation energy required for a reaction
enzymes
what type of proteins are enzymes
globular proteins
they are roughly spherical
enzymes
an example of enzymes breaking down molecules
digestive enzymes help break down food into smaller molecules e.g. carbohydrases break down carbohydrates
enzymes
an example of enzymes building molecules
enzymes involved in DNA replication help to build molecules e.g. DNA polymerase
enzymes
what is a substrate
a substance thats acted upon by an enzyme
enzymes
what is an active site
the region on the surface of an enzyme where a substrate can attach itself (enzyme-substrate complex) where the catalysed reaction takes place
the shape of substrate and active site are complimentary
enzymes
what does it mean when an enzyme is specific
an enzyme only catalyses one specific chemical reaction since only one substrate will be the correct shape
enzymes
how does temperature affect enzyme activity
as temp increases enzyme reactions become faster because the molecules have more energy
enzymes
what happens to enzymes if the temperature gets too high
they vibrate rapidly and break the weak bonds that hold the tertiary structure this changes the shape of the active site and the enzyme becomes denatured
enzymes
how does pH affect enzyme activity
acids and alkalis denature enzymes
hydrogen ions (H+) and hydroxyl ions (OH-) in alkalis can disrupt the weak bonds and change the shape of the active site
cell structure
what are organelles
parts of cells- each one has a specific function
cell structure
4 things animal and plant cells have in common
- NUCLEUS-contains genetic material thats controls what the cells do
- CYTOPLASM-contains enzymes that speed up biochemical reactions
- CELL-SURFACE MEMBRANE- holds cell together and controls what goes in and out
- MITOCHONDRIA- where glucose and oxygen are use in respiration to provide energy to the cell
cell structure
3 things plant cells have that animal cells dont
- RIGID CELL WALL- made from cellulose and gives the cell support
- VACUOLE- contains cell sap, a weak solution of sugar and salts
- CHLOROPLASTS- contain chlorophyll for photosynthesis
cell structure
How big is a prokaryote compared to a eukaryote
prokaryotes are roughly tenth the size of a eukaryote
cell structure
how is the DNA stored in a prokaryote
they dont have anucleus so the DNA floats freely in the cytoplasm
some prokaryotes also have rings of DNA called plasmids
microscopes
how much can a light microscope magnify objects
up to 1500 times
microscopes
what does a light microscope allow you to see
individual cells and organelles inside
1. if stained the nucleus is visible and is darker than the cytoplasm
2. tiny mitochondria and the black line of the cell membrane= visible
3. in plant cells the cell wall, chloroplasts and the vacuole can be seen
microscopes
by how much can an electron microscope magnify objects
they can magnify objects more than 500,000 times
microscopes
what is the image thats recorded by an electron microscope called
an electron micrograph
cell structure
what does DNA stand for
deoxyribonucleic acid
cell structure
what is DNA
the coded information needed for making proteins
cell structure
what happens to the chromosomes during cell division
the chromosomes carrying the long DNA molecules coil up, becoming shorter and thicker
cell structure
how big are mitochondria
about the size of bacteria so can be seen with a light microscope
cell structure
word equation for aerobic respiration in mitochondria
glucose+oxygen–> carbon dioxide+water (+enrgy)
cell structure
what does ATP stand for
adenosine triphosphate
cell structure
what is ATP used for in cells
- muscle contraction
- active transport
- building large molecules
cell structure
what is the cell wall made of
bundles of long straight cellulose molecules (microfibrils)
cell structure
describe the membranes of a mitchondrion
each mitochondrion has a smooth outer membrane and a folded inner membrane
