DNA and Proteins Study Notes PDF

DNA and proteins A character trait is a physical or psychological or physiological attributes that may vary from 1 individual to another in the same species. Examples eye colour capacity to digest and taste to adventure. A chromosome is a structure that is formed when chromatins contract. Humans...

DNA and proteins A character trait is a physical or psychological or physiological attributes that may vary from 1 individual to another in the same species. Examples eye colour capacity to digest and taste to adventure. A chromosome is a structure that is formed when chromatins contract. Humans have 23 pairs of chromosomes. A karyotype is an ordered representation of an individual's chromosomes obtained by grouping them into pairs according to size. A gene is a DNA segment that contains information for making proteins. The genome consists of all the genes we receive from our parents A nucleotide is a series of chemical units. pairing of nitrogenous bases in DNA. The nitrogenous bases of nucleotides pair only with a single other nitrogenous base. Protein synthesis A protein is a molecule that plays a specific role in the functioning of an organism and in the expression of its character traits. An amino acid is a molecule that can combine with other amino acids to form proteins. A protein synthesis is a creation of proteins by cells. DNA RNA Is a double strand Is a single strand Thymine (T) Uracil (U) Deoxyribose sugars Ribose sugar Stuck inside cell's nucleus Can exit the nucleus Messenger RNA (mRNA) Transfer (tRNA) Acts as a messenger for carrying Transfers the amino acids in the cell's instructions about the gene to the cytoplasm to the ribosomes. ribosomes. Protein synthesis Transcription Attachment Translation End ▫ Uracil (U) ▫ Ribosomes ▫ Each triplet ▫ UAA, UAG replaces read the codes for an OR UGA thymine (T) nucleotides amino acid means stop ▫ DNA unzips in triplets ▫ Amino acids ▫ The protein ▫ DNA cannot ▫ The AUG chain released exit the triplet together ▫ It folds to go nucleus means start perform its  ▫ Making a ▫ Happens ▫ Happens on function in copy of DNA inside the the the body (the code) cell but ribosomes outside the nucleus Transcription of Attachments of the Translation of the End of protein DNA into messenger RNA to messenger RNA synthesis messenger RNA the ribosome into a protein Genetics Heredity is the transmission of parents character traits to their offsprings A generation is a group of individuals that are the offspring of the same parents An allele is a possible form of a gene. The nucleotide sequence is different ACG ➝ AGC Both alleles code the same gene but express that gene in a different way A homozygote is an individual with two identical alleles for a given characteristic trait A heterozygote is an individual with two different alleles for a given characteristic trait A dominant allele is an allele that is expressed over a recessive allele A recessive allele is an allele that is not expressed when paired with a dominant allele Blood Types : A and B are co-dominant over allele O A genotype is an individual's genetic inheritance. It describes all of an individual's allele for specific genes A phenotype is the way in which a geno type expresses itself. It describes the appearence or state of an individual for one or more character traits. Mendel laws of heredity 1. Law of segregation of alleles: the two alleles for a character trait separate when gametes are formed. One gamete has only one of the two alleles 2. Law of independent assortment of character traits: during gamete formation, the alleles for different character traits, which up until then had been in pairs become separated gametes.  Rules for describing genotypes Each allele is represented by a letter. It is the first letter of the dominant allele Dominant allele = capital letter Recessive allele – lower case of the same letter One characteristic Punnett square 1. Determine the genotypes of the two parents 2. Find all possible genotypes for the gametes of each parent and write them in circles (Law of segregation) 3. Place the possible gametes from one parent on top of the square and the other on the side 4. Indicate all the possible gamete combinations; enter the genotypes and the phenotypes Two characteristic Punnett square 1. Determine the genotypes of the two parents 2. Find all possible genotypes for the gametes of each parent and write them in circles (Law of independent assortment of character traits) 3. Place the possible gametes from one parent on top of the square and the other on the side 4. Indicate all the possible gamete combinations; enter the genotypes and the phenotypes Study Notes on DNA and Proteins Character Traits A character trait refers to physical, psychological, or physiological attributes that can vary among individuals of the same species. Examples include: Eye color Capacity to digest Taste preferences Adventurousness Chromosomes and Karyotypes A chromosome is formed when chromatins contract. Humans possess 23 pairs of chromosomes. A karyotype is an ordered representation of an individual's chromosomes, grouped into pairs based on size. Genes and the Genome A gene is a segment of DNA that contains the information necessary for making proteins. The genome encompasses all the genes inherited from our parents. Nucleotides and DNA Structure A nucleotide consists of chemical units that include nitrogenous bases. In DNA, nitrogenous bases pair specifically with one another: Adenine (A) pairs with Thymine (T) Cytosine (C) pairs with Guanine (G) Protein Synthesis A protein is a molecule that plays a crucial role in an organism's functioning and the expression of character traits. Proteins are made up of amino acids, which can combine to form various proteins. The process of protein synthesis occurs in cells and involves several key components: DNA: Double-stranded structure containing genetic information. RNA: Single-stranded molecule that plays a role in protein synthesis. Types of RNA There are different types of RNA involved in protein synthesis: Messenger RNA (mRNA): Carries instructions from DNA to ribosomes. Transfer RNA (tRNA): Transfers amino acids to ribosomes during protein synthesis. Steps of Protein Synthesis Protein synthesis involves several steps: 1. Transcription: DNA unzips, and mRNA is created as a copy of the DNA code. 2. Attachment: mRNA attaches to ribosomes. 3. Translation: Ribosomes read mRNA nucleotides in triplets, where each triplet codes for an amino acid. 4. Termination: Specific triplets (UAA, UAG, UGA) signal the end of protein synthesis, and the protein is released and folded to perform its function. Genetics and Heredity Heredity is the process by which parents pass on character traits to their offspring. A generation refers to a group of individuals that are the offspring of the same parents. Alleles and Genotypes An allele is a variant form of a gene, differing in nucleotide sequence. For example, ACG can change to AGC. Alleles can be: Homozygote: An individual with two identical alleles for a trait. Heterozygote: An individual with two different alleles for a trait. A dominant allele is expressed over a recessive allele. Blood types A and B are co- dominant over allele O. Genotype and Phenotype A genotype describes an individual's genetic inheritance, while a phenotype refers to the observable expression of that genotype, including physical appearance and traits. Mendel's Laws of Heredity Mendel's laws include: Law of Segregation: The two alleles for a trait separate during gamete formation, with each gamete receiving only one allele. Law of Independent Assortment: Alleles for different traits segregate independently during gamete formation. Genotype Representation Genotypes are represented by letters: Dominant alleles are indicated by capital letters. Recessive alleles are indicated by lowercase letters. Punnett Squares Punnett squares are used to predict genotypes and phenotypes: One Characteristic Punnett Square: o Determine the genotypes of the two parents. o Identify possible gametes for each parent (Law of Segregation). o Place gametes in the square and indicate combinations. Two Characteristics Punnett Square: o Determine the genotypes of the two parents. o Identify possible gametes for each parent (Law of Independent Assortment). o Place gametes in the square and indicate combinations.