B1: You and your genes

"What is the genome and what does it do?"

"The genome is the entire genetic material of an organism and it determines its characteristics."

"What is a chromosome?"

"A chromosome is a thread-like structure of DNA that carries genetic information in the form of genes."

"What is a gene?"

"A gene is a length of DNA that codes for a particular protein."

"What is an allele?"

"An allele is one of a number of different versions of a gene."

"What is a genotype?"

"Genotype is the genetic makeup of an organism, consisting of all the alleles present."

"What is a phenotype?"

"Phenotype is the observable features of an organism as a result of the expression of particular alleles and environmental interaction."

"What are eukaryotic cells?"

"Eukaryotic cells, such as plant and animal cells, contain a nucleus and membrane-bound organelles like ribosomes and mitochondria."

"What are prokaryotic cells?"

"Prokaryotic cells, such as bacteria, do not contain a nucleus or membrane-bound organelles and store genetic material in plasmids."

"What are plasmids?"

"Plasmids are circular loops of DNA found in the cytoplasm of prokaryotic cells."

"What determines most characteristics of an organism?"

"Most characteristics are determined by the genome and different alleles, though the environment can also influence them."

"What is DNA and what does it do?"

"DNA stands for deoxyribonucleic acid and contains instructions for the cell, including protein synthesis."

"What is the structure of DNA?"

"DNA is a polymer made of nucleotides forming two long strands that twist into a double helix."

"What are nucleotides?"

"Nucleotides are molecules made of a sugar, a phosphate group, and a base; there are four types of bases in DNA."

"What is protein synthesis?"

"Protein synthesis is the process of making proteins from amino acids using mRNA as a template from DNA."

"Where does mRNA synthesis occur?"

"mRNA is synthesized in the nucleus from a section of DNA."

"Where does translation occur?"

"Translation occurs at the ribosome, where amino acids are joined to form proteins according to the mRNA code."

"What are mutations?"

"Mutations are changes in the DNA sequence which can create new alleles and affect the phenotype."

"What is inheritance?"

"Inheritance is the transmission of genetic information from parents to offspring."

"What is a gamete?"

"A gamete is a reproductive cell carrying one half of each chromosome pair, e.g., egg or sperm."

"What does homozygous mean?"

"Homozygous refers to having two identical alleles for a particular gene."

"What does heterozygous mean?"

"Heterozygous refers to having two different alleles for a particular gene."

"What is a dominant allele?"

"A dominant allele is expressed in the phenotype if present and masks a recessive allele."

"What is a recessive allele?"

"A recessive allele is only expressed in the phenotype if no dominant allele is present."

"What is single gene inheritance?"

"Offspring inherit one allele from each parent for each gene; traits can be homozygous or heterozygous, dominant or recessive."

"How are ratios predicted in single gene crosses?"

"Ratios are predicted using Punnett squares showing the probability of each allele combination in offspring."

"How is sex determined in humans?"

"Sex is determined by the sex chromosomes: females are XX and males are XY. Gametes carry one sex chromosome each, so offspring have a 50% chance of being male or female."

"Who discovered basic genetics?"

"Gregor Mendel discovered the principles of genetics through experiments with pea plants in 1866."

"What is genetic engineering?"

"Genetic engineering is artificially altering genes in a cell to give organisms desirable characteristics or produce proteins."

"How is genetic engineering performed?"

"1) Locate and isolate the desired gene. 2) Insert it into a vector. 3) Introduce it into a host cell. 4) Select successfully modified cells."

"Give an example of genetic engineering in crops."

"Frost-resistant strawberries using an anti-freeze gene from arctic fish or Golden rice producing beta-carotene."

"What are benefits of genetic engineering?"

"Improved crop yields, provision of nutrients, better medicines, and genetic screening for healthcare."

"What are risks of genetic engineering?"

"Environmental impacts, potential health risks, ethical issues like 'designer babies,' and high costs."