Level 2 Biology Key terms & definitions Flashcards
Organelle
Any specialised structure inside a cell that performs a special function.
Respiration Word Equation
Glucose + oxygen → carbon dioxide + water +energy
Respiration Balanced Chemical Equation
C₆H₁₂O₆ + 6O₂ → 6CO₂ +6H₂O + energy
Photosynthesis Word Equation
Sunlight + Carbon dioxide + Water → Glucose + Oxygen
Photosynthesis Balanced Chemical Equation
Sunlight + 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
What are the 2 types of Respiration?
Anaerobic respiration & Aerobic respiration
What are the 2 types of Photosynthesis
The light dependent reactions & the light independent reactions (Calvin cycle)
What is a Homologous pair
Matching chromosomes containing the same genes, one having come from either parent.
What is a Gamete
A sex cell
What is a Recessive Gene
An allele that is only expressed if there is no dominant allele present
What is Homozygous
The genotype that has 2 alleles the same e.g BB
What is a Mutation
A permanent change in genetic code
What is Mitosis
Cell division that occurs in the body cells for growth and repair
What is Meiosis
Cell division that occurs in the sex organs to produce sex cells
What is Sexual reproduction
A type of reproduction that uses gametes producing variation in the new individual
What is a Zygote
The cell formed when the sperm cell fuses with the egg cell.
What is Fertilisation
The process where two sex cells fuse together to form a zygote
What is a Dominant gene
This is an allele which will be expressed even if only one is present in the genotype e.g Bb
What is a Gene
A section of chromosome that codes for a particular protein and therefore a trait.
What is a Chromosome
A strand of DNA which contains many genes.
What is Phenotype
The expression of the genotype as a visible trait
What is Heterozygous
The genotype with 2 different alleles e.g Bb
What is Semi conservative
Each double DNA strand is composed of one new and one old strand
What is a Carrier
An individual that has inherited a gene but does not display the trait
What is Genotype
The alleles you carry e.g BB, Bb, bb
What is a Trait
A characteristic that is inherited e.g eye colour
What is a Allele
Different version of the same gene
What is Haploid
A cell with half the number of chromosomes.
What is a Nucleotide
A unit made up of a base, a sugar and a phosphate
What is DNA (simple version?)
It is a double helix shaped chemical which carries genetic information
What is Diploid
A cell with a full set of chromosomes.
Definition of Anticodon
Three consecutive bases on the tRNA
Definition of Codon
Three consecutive bases on the mRNA
Definition of Deletion Mutation
A mutation on the DNA where a base(s) is removed, resulting in a frame shift.
What is DNA (complicated version?)
Deoxyribose nucleic acid, A joins with T, C joins with G. Double stranded, helix shaped large molecule, a whole chromosome. Deoxyribose sugar.
Definition of Enzyme
A folded protein which acts as a biological catalyst to speed up the rate of a chemical reaction in an organism.
Definition of Frameshift
Change in bases that the ribosome reads
Definition of Gene
A piece of DNA which codes for the making of a protein/feature
Definition of Gene expression
The process where the instructions on our DNA are converted into a functional protein, includes transcription, translation and protein folding.
Definition of Insertion mutation
A mutation on the DNA where a base(s) is added resulting in a frameshift.
Definition of Metabolic pathway
A series of enzyme-controlled reactions, where the product of one reaction becomes the substrate of the next
Definition of Missense mutation
A change of the base on the DNA which codes for a different amino acid. This may or may not alter the shape of the protein and therefore it’s function.
Definition of mRNA
Messenger mRNA. Made during transcription in the nucleus. Carries the instructions to the ribosome to make a polypeptide chain. Contains codons.
Definition of Mutagen
Environmental factor which causes the mutation e.g agent orange, X-rays etc
Definition of Mutation
A sudden, permanent change in the bases on the DNA
Definition of Non-sense mutation
A change of the base on the DNA which changes the instructions, so a STOP codon occurs in the wrong place. Protein is greatly affected.
Definition of Peptide bond
Bond formed between 2 amino acids during translation
Definition of Phenotype
The physical appearance of a feature
Definition of Point mutation
A change of only one or a few bases on the DNA
Definition of Protein
A substance made up of many amino acids joined together to form a polypeptide chain, which gets folded into a functional protein (enzymes are a type of protein)
Definition of Redundancy
The fact that multiple codons code for the same amino acid, e.g CCU, CCC, CCA and CCG all code for the amino acid Pro
Definition of RNA
Ribonucleic acid. A bonds with U and G bonds with C. Three types, tRNA, mRNA and rRNA. Single stranded and shorter than DNA. Sugar is ribose
Definition of Same-sense mutation
A change of the base on the DNA where the bases still code for the same amino acid. This is due to the redundancy of the genetic code.
Definition of Silent mutation
A mutation that is neither favourable nor harmful, that remains in a population
Definition of Start codon
The start signals on the mRNA which initiates translation. Always AUG.
Definition of Stop codon
These 3 codons on the mRNA (UAA, UAG, UGA) do not code for an amino acid therefore telling the ribosome where to stop translation.
Definition of Substitution mutation
A mutation where the base(s) on the DNA are swapped
Definition of Transcription
The process by which DNA going to mRNA, occurs in the nucleus. Controlled by RNA polymerase.
Definition of Translation
The process by which mRNA going to polypeptide chain, occurs in the cytoplasm on the ribosome.
Definition of Triplet
Three consecutive bases on the DNA
Definition of tRNA
Transfer RNA. Carries an amino acid to the ribosome. 3 bases on the mRNA=an anticodon.
What is gene expression
Gene expression is the process by which information from a gene is used to make a protein.
The base sequence of a DNA molecule codes for?
The base sequence of a DNA molecule codes for the amino acids that make up proteins.
A sequence of 3 bases in DNA (a triplet) codes for?1
A sequence of 3 bases in DNA (a triplet) codes for 1 amino acid
A sequence of many amino acids joined together with _______ bonds forms a ____________
A sequence of many acids joined together with PEPTIDE bonds forms a POLYPEPTIDE.
One gene codes for one Polypeptide (basic protein most proteins made of many ___________)
One gene codes for one Polypeptide (basic protein most proteins made of many POLYPEPTIDES)
