TERM 2 BIOLOGY- Sem 1 24'

B1.2, B2.2, A1.2, B1.2, B1.1

generalised structure of an amino acid

generalised structure of an amino acid

dipeptide

two amino acids

amino acids are joined together by a

type of covalent bond called a ‘peptide bond’

anabolism

synthesis of complex molecules from simpler molecules

polypeptide

many amino acids

condensation reactions remove water to form

a peptide bond

how many different amino acids are there

20

can plants manufacture all 20 amino acids

yes

can animals manufacture all 20 amino acids

no

how many amino acids are essential

9

how many amino acids are non-essential

11

there is an infinite variety of

possible peptide chains

DNA to RNA to

Polypeptide

sequence of amino acids is determined by

DNA

Proteome

set of proteins made by an organism

Denaturation

permanent change to the structure of a protein

how does heat affect polypeptides

breaks bonds between amino acids

how does extreme ph affect polypeptides

higher or lower breaks bonds or causes new interactions

Organelle

structure that is specialised for a specific function within a cell

cell structures that are not organelles

cell wall, cytoskeleton, cytoplasm

no membrane

ribosomes, centrioles, microtubules, proteasomes, nucleoli

single membrane

vesicles and vacuoles, rough er, smooth er, golgi, lysosomes

double membrane

nuclei, mitochondria, chloroplasts, amylopasts, chromoplasts

cell walls are not organelles because

they are extracellular structures

cytoskeletons are not organelles because

they consist of narrow protein filaments and not discrete enough

cytoplasm is not a discrete structure because

many different structures and functions

how many organelles do prokaryotic cells have compared to eukaryotes

fewer

translation can not begin in eukaryotes until

mRNA has passed out of the nucleus via the pores in the nuclear membrane

why does translation wait to begin in eukaryotes for mRNA

allows mRNA to perform post-transcriptional modification

advantages of compartmentalisation in the cytoplasm of cells

enzymes and substrates can be much more concentrated, substances that could cause damage kept inside the membrane, conditions like ph can be maintained, organelles with their contents can be moved around within the cell, larger area of membrane available for processes

adaptations of the mitochondrion for production of a ATP by aerobic cell respiration

outer membrane separates the contents of the mitochondrion from the rest of the cell, cristae projections of the inner membrane that increase surface area, matrix fluid filling the compartment containing all enzymes and substrates for the krebs cycle

adaptations of the chloroplasts for photosynthesis

double membrane, extensive system of internal membranes called thylakoids, small fluid-filled spaces inside the thylakoids, colourless fluid around the thylakoids

what do thylakoid membranes ensure

the chloroplast has a large light-absorbing capacity often arranged in stacks called grana

stroma

a compartment of the plant cell in which the enzymes needed for the calvin cycle

functional benefits of the double membrane

the hydrophobic core is never exposed to water, pores are formed using integral proteins

where are mRNA, tRNA and ribosomes produced

in the nucleus and exported to the cytoplasm

structure and function of free ribosomes and of the rough er

produce proteins used within the cell, on rough er produce proteins for secretions (exported from the cell)

structure and function of the golgi apparatus

processes proteins from the rough ER, packages into the vesicles for secretion

structure and function of vesicles in cells

formed during endocytosis and are made within cells by pinching of a section of membrane to surround a substance used to move things around in cells

DNA is

the genetic material of all living organisms

is dna a nucleic acid

yes

what are the 4 major types of molecules

carbohydrates, lipids, proteins, nucleic acids

functions of nucleic acids

pass information between generations, code for protein productions

types of nucleic acids

DNA and RNA

DNA function

passes heredity information between generations of cells, codes for making RNA during transcription

nucleotide structure

sugar-phosphate backbone structure

RNA function

codes for making proteins during translation

what are the 3 types of RNA involved in protein synthesis

mRNA, rRNA , tRNA

some viruses do not have DNA and use

RNA as their genetic material

what are nucleic acids

chains of nucleotides combined in condensation reactions

what is the nucleotide considered as

the monomer or the nucleic acid polymer

parts of a nucleotide

purine or prymidine nitrogenous base, five-carbon pentose sugar, negatively charged phosphate group

pentose sugars

have 5 carbon atoms, nitrogenous base connects off of carbon 7, carbon 5 branches out of the ring

nucleic acid condensation reaction

the backbone is formed when nucleotides combine in a condensation reaction

the molecular DNA double-helix shape is formed by two sugar-phosphate backbones

that run antiparallel to each other and twist together in a helical shape

mRNA

encodes proteins

tRNA

acts as adaptor between mRNA and amino acids

rRNA

forms the ribosome

the sugar-phosphate backbones of nucleic acids provides

structural support

sharing electrons in the covalent bond between sugar and phosphate provides

strength to the structure

five different nitrogenous bases

adenine, thymine, cytosines, guanine, uracil

nitrogenous bases

the bases all have different molecular structures however all five contain nitrogen atoms

Gene

specific sequence of nitrogenous bases in DNA nucleotides that codes for making of a protein

process of decoding a gene consists of two major steps

transcription and translation

RNA as a polymer is formed by

condensation of nucleotide monomers

four nitrogenous bases in RNA

adenine, uracil, cytosine, guanine

DNA as a double helix made of

two antiparallel strands of nucleotides

four nitrogenous bases in DNA

adenine, thymine, cytosine, guanine

DNA backbone is formed when nucleotides

combine in a condensation reaction

two strands of the double helix run in

opposite directions

nitrogenous bases join together by

hyrdrogen bons

sugar in DNA

deoxyribose

sugar in RNA

ribose

how many backbones in DNA

2

how many backbones in RNA

1

DNA uses thymine

RNA uses uracil

DNA function

passes heredity information between generations, codes for making RNA during transcription

RNA function

codes for making proteins during translation, mRNA, rRNA and tRNA involved in protein synthesis

in the eukaryotic cell DNA

located in the cell nucleus

in the eukaryotic cell RNA

made in the nucleus for transcription but transported to the cytoplasm for translation

in the prokaryotic cell DNA

contained in the nucleoid

in the prokaryotic cell RNA is

found in the cytoplasm

in DNA replication the new strand is built by

by reading the template and adding the complementary DNA nucleotide (semiconservative)

base pairing during transcription

enzyme RNA polymerase builds on RNA strand by reading the DNA template and adding the complementary RNA nucleotide

base pairing during translation

amino acids are brought to the ribosome by tRNA, tRNA forms a temporary bond to the mRNA using complementary base pairing

DNA as an information storage molecule

stores information in the sequence of the nitrogenous bases

What is the capacity of DNA to store information

it is limitless

conservation of the genetic code across all life forms as evidence of universal common ancestry

the sequence of bases forms a code, the genetic code is universal, the universality of the genetic code is due to the LUCA

Pentose sugar

function of codons

code for amino acids

how is a protein made in a cell by the process of translation

RNA is translated using tRNA, this happens in the cytoplasm, mRNA attaches to the ribosomes ribosome forms two subunits, using tRNA the sequence of mRNA is translated in a sequence of amino acids and a polypeptide is formed, once coming to a stop the polypeptide chain is formed and breaks off

Explain the significance of complementary base pairing in DNA

connects two sugar phosphate backbones resulting in stability and the shape of the double helix, ensure one parent strand is present when a new DNA strand is being created, codes for proteins

carbohydrates

carbon, hyrdrogen, oxygen

what are carbohydrates composed of

recurring monomers called monosaccharides

monosaccharides

single sugars

what do monosaccharides form

ring structures as a result of a chemical reaction between functional groups at opposite ends of the molecule

monosaccharide cyclration

hydroxyl group links to a carbonyl group to form a cyclic structure connected by an oxygen atom

how many carbons do most monosaccharides have

5 or 6

carbons

pentose sugars