Genes & Inheritance: Quiz Review
Grade 7 Science Preparing for the Quiz Understanding Life's Blueprint
Learning Objectives - What I Can Do
I can explain what genes are and their role in inheritance I can describe how traits are passed from parents to offspring I can identify dominant and recessive alleles I can explain Mendel's contributions to genetics I can describe how mutations affect genetic variation
What Are Genes?
Genes are sections of DNA that code for specific traits Located on chromosomes in the nucleus Act like instruction manuals for building proteins Humans have about 20,000-25,000 genes Each gene has a specific location called a locus
Dominant vs. Recessive Traits
{"left":"Dominant alleles are expressed when present\nRepresented by CAPITAL letters (A, B, C)\nOnly need ONE copy to show the trait\nExamples: Brown eyes, Dark hair","right":"Recessive alleles are hidden by dominant ones\nRepresented by lowercase letters (a, b, c)\nNeed TWO copies to show the trait\nExamples: Blue eyes, Red hair"}
Punnett Square Practice
Cross: Brown eyes (Bb) × Blue eyes (bb) Step 1: Write parent genotypes Step 2: Determine possible gametes Step 3: Fill in the square Step 4: Calculate probability ratios
Gregor Mendel's Legacy
"The Father of Genetics discovered the fundamental laws of inheritance through his pea plant experiments in the 1860s."
Chromosomes and Genetic Material
Humans have 46 chromosomes (23 pairs) Each chromosome contains hundreds to thousands of genes Sex chromosomes determine gender (XX = female, XY = male) Chromosomes come in homologous pairs One chromosome from each parent in every pair
Types of Mutations
Think-Pair-Share: Genetic Variation
Why don't you look exactly like your siblings? List 3 sources of genetic variation How does genetic variation help species survive?
Quiz Preparation Checklist
Review vocabulary: gene, allele, chromosome, mutation Practice Punnett squares with different crosses Understand dominant vs. recessive inheritance Know Mendel's contributions to genetics Explain sources of genetic variation Be ready to analyze inheritance patterns