inheritance A- topic 14

• chromosomes are long coils of DNA located in the nucleus
• inherited diseases- some diseases are inherited because they are caused by a faulty allele, doctors can use genetic diagrams and family pedigrees to help parents work out their chances of having a child with the disease and make choices about the future
• homozygous is two identical alleles of a particular gene (AA)
• heterozygous is two different alleles of a particular gene (Aa)
• nucleus is the organelle which contains the genetic information within a cell
• cell is the smallest structural unit of a living organism
• phenotype is the set of observable characteristics, what an organism physically looks like
• allele is different forms of the same gene
• monohybrid is the allele of only one characteristic is observed in both the mother and father. the genotype and phenotype of the offspring are then observed for that one trait only
• gene is a distinct sequence of nucleotides on a chromosome which code for a particular sequence of amino acids to form a specific protein
• recessive refers to a trait that requires 2 copies of the same gene to be expressed. the trait is not expressed unless the individual is homozygous
• dominant refers to a trait that is expressed even if there is only 1 copy of a gene, trait is always expressed
• biological sex is controlled by the 23rd pair of chromosomes, female- xx. male- xy
• genotype is the organisms genes
• DNA is a long molecule that contains our unique genetic code its in a double helix shape, A (Adenine) T (thymine) C (cytosine) G (guanine)
• karotypes are a way of presenting chromosomes
• polygenic inheritance, most traits are polygenic, they are controlled by many genes, each of which have a small effect
• transcription is DNA- RNA using base pair rules
• cells read the DNA sequences as triplets of bases
• protein synthesis occurs in the ribosome
• codons are a group of three bases which are complementary to the anticodons on the TRNA
• anticodons are a group of 3 bases which are complementary to the codons of the MRNA
• the 2 stages of protein synthesis are transcription and translation
• transcription steps, occurs in the nucleus, DNA unwinds and unzips, strands separate, MRNA leaves the nuclear envelope and goes to ribosomes for translation, DNA rewinds back into double helix shape
• there are 20 naturally occurring amino acids in body cells
• translation steps, occurs in ribosome, MRNA attaches to the ribosomes, the ribosome reads the codons on the MRNA and attaches the complementary TRNA anticodon carrying the specific amino acid. the ribosome ensures the correct amino acid are in the correct sequence
• function of MRNA, a transcribed template of the DNA which is read by the ribosome to produce the corresponding amino acids, have codons, leave the nuclear envelope and goes to the ribosomes for translation
• ribosomes read the codons on the MRNA and uses this to join the correct amino acids in the correct order
• replication is DNA-DNA using base pair rules
• DNA base pair rules is adenine and thymine, guanine and cytosine
• RNA base pair rules is adenine and uracil, guanine and cytosine
• RNA molecule is single stranded, contains uracil instead of thymine, shorter then DNA
• DNA molecule is double stranded, contains thymine instead of uracil, longer then RNA
• translation is RNA- amino acids
• function of TRNA is to carrier molecules which bring amino acids to the ribosome, have anticodons, codons and anticodons ensure the correct amino acid is paired up with the triple code of bases
• codominance is a type of inheritance where both alleles for a gene are expressed in the phenotype of the offspring
• a cell contains a nucleus, many chromosomes are contained in a nucleus, each chromosome consist of long coils of DNA, DNA contains the genetic material of the organism
• Punnet square

  
• Family pedigrees