6.04 Semester Test: Biology - Part 1

6.04 Semester Test: Biology - Part 1: A Comprehensive Review

This comprehensive guide is designed to help students prepare for their 6.04 Biology semester test, specifically focusing on Part 1. We'll cover key concepts, provide practice questions, and offer strategies for success. Remember to consult your textbook and class notes for specific details relevant to your curriculum. This guide serves as a supplementary resource, not a replacement for your own learning materials.

I. Cellular Biology: The Foundation of Life

This section typically covers the fundamental building blocks of life – cells. Mastering these concepts is crucial for success in the 6.04 semester test.

A. Cell Structure and Function:

• Prokaryotic vs. Eukaryotic Cells: Understand the key differences between these two cell types. Focus on the presence or absence of membrane-bound organelles, such as a nucleus, mitochondria, and chloroplasts. Practice identifying cells based on their structural characteristics. Key terms: nucleus, cytoplasm, ribosomes, cell membrane, cell wall, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, vacuoles.

• Organelle Functions: Know the specific roles of each major organelle within both plant and animal cells. For example, what is the function of the mitochondria (powerhouse of the cell)? How does the Golgi apparatus process and package proteins? What is the role of the lysosomes in waste breakdown? Practice Question: Describe the function of the endoplasmic reticulum (smooth and rough) and its connection to protein synthesis and lipid metabolism.

• Cell Membrane Structure and Transport: Understand the fluid mosaic model of the cell membrane and the role of phospholipids, proteins, and carbohydrates. Master the different types of membrane transport: passive transport (diffusion, osmosis, facilitated diffusion) and active transport (endocytosis, exocytosis). Key terms: phospholipid bilayer, selective permeability, diffusion, osmosis, facilitated diffusion, active transport, endocytosis, exocytosis. Practice Question: Explain the difference between osmosis and diffusion. Give examples of each.

B. Cell Processes:

• Photosynthesis: Understand the overall process of photosynthesis, including the light-dependent and light-independent reactions (Calvin cycle). Know the reactants and products of photosynthesis and the role of chlorophyll. Key terms: chlorophyll, stomata, light-dependent reactions, light-independent reactions (Calvin cycle), ATP, NADPH, glucose. Practice Question: Explain how the light-dependent reactions provide energy for the light-independent reactions.

• Cellular Respiration: Understand the overall process of cellular respiration, including glycolysis, the Krebs cycle, and the electron transport chain. Know the reactants and products of cellular respiration and the role of ATP in energy production. Key terms: glycolysis, Krebs cycle, electron transport chain, ATP, NADH, FADH2. Practice Question: Compare and contrast aerobic and anaerobic respiration.

• Cell Cycle and Mitosis: Understand the stages of the cell cycle (interphase, mitosis, cytokinesis) and the events that occur during each stage. Know the importance of mitosis in growth and repair. Key terms: interphase, prophase, metaphase, anaphase, telophase, cytokinesis, chromosomes, chromatids. Practice Question: Describe the events that occur during metaphase of mitosis.

• Meiosis: Understand the process of meiosis, including the two divisions (meiosis I and meiosis II) and the resulting formation of four haploid gametes. Know the importance of meiosis in sexual reproduction and genetic variation. Key terms: meiosis I, meiosis II, homologous chromosomes, crossing over, genetic variation, gametes. Practice Question: Explain how crossing over contributes to genetic variation.

II. Genetics: The Blueprint of Life

This section delves into the fascinating world of heredity and how traits are passed from one generation to the next.

A. Mendelian Genetics:

• Basic Principles of Inheritance: Understand Mendel's laws of segregation and independent assortment. Be able to predict the genotypes and phenotypes of offspring using Punnett squares. Key terms: genotype, phenotype, allele, homozygous, heterozygous, dominant, recessive, Punnett square. Practice Question: A homozygous dominant individual (BB) for brown eyes crosses with a homozygous recessive individual (bb) for blue eyes. What are the genotypes and phenotypes of the offspring?

• Monohybrid and Dihybrid Crosses: Practice solving problems involving both monohybrid (one trait) and dihybrid (two traits) crosses. Understand how to determine probabilities of offspring inheriting specific combinations of alleles. Practice Question: In pea plants, tall (T) is dominant to short (t), and yellow seeds (Y) are dominant to green seeds (y). A plant heterozygous for both traits (TtYy) is crossed with a plant homozygous recessive for both traits (ttyy). What are the possible genotypes and phenotypes of the offspring, and their probabilities?

B. Non-Mendelian Genetics:

• Incomplete Dominance and Codominance: Understand these exceptions to Mendel's laws. Be able to predict the phenotypes of offspring when alleles show incomplete dominance (blending of traits) or codominance (both alleles expressed equally). Key terms: incomplete dominance, codominance, multiple alleles. Practice Question: In snapdragons, red flowers (R) and white flowers (W) show incomplete dominance. What phenotype would you expect from a cross between a red-flowered plant and a white-flowered plant?

• Sex-Linked Traits: Understand how traits located on the sex chromosomes (X and Y) are inherited. Be able to solve problems involving sex-linked traits, such as color blindness or hemophilia. Key terms: sex chromosomes, sex-linked traits, X-linked, Y-linked. Practice Question: A woman who is a carrier for color blindness (X^CX^c) marries a man with normal vision (X^CY). What is the probability of their sons inheriting color blindness?

C. Molecular Genetics:

• DNA Structure and Replication: Understand the structure of DNA (double helix) and the process of DNA replication (semiconservative replication). Key terms: DNA, nucleotides, base pairing, replication, semi-conservative replication. Practice Question: Explain the role of DNA polymerase in DNA replication.

• Protein Synthesis (Transcription and Translation): Understand the processes of transcription (DNA to mRNA) and translation (mRNA to protein). Key terms: transcription, translation, mRNA, tRNA, rRNA, codons, anticodons, ribosomes. Practice Question: Explain the role of tRNA in translation.

• Mutations: Understand the different types of mutations (gene mutations and chromosomal mutations) and their potential effects on phenotype. Key terms: mutation, gene mutation, chromosomal mutation, point mutation, frameshift mutation. Practice Question: Explain the difference between a point mutation and a frameshift mutation.

III. Evolution and Ecology: The Interconnectedness of Life

This section explores the vast tapestry of life on Earth, examining how populations change over time and how organisms interact with their environment.

A. Evolution:

• Natural Selection: Understand the principles of natural selection: variation, inheritance, overproduction, and differential survival and reproduction. Be able to explain how natural selection leads to adaptation and speciation. Key terms: natural selection, adaptation, speciation, fitness, evolution, genetic drift, gene flow. Practice Question: Explain how natural selection can lead to the development of antibiotic resistance in bacteria.

• Evidence for Evolution: Understand the different types of evidence that support the theory of evolution, including fossil evidence, comparative anatomy, embryology, molecular biology, and biogeography. Practice Question: Explain how comparative anatomy provides evidence for evolution.

B. Ecology:

• Ecosystem Structure: Understand the different levels of organization in an ecosystem (organism, population, community, ecosystem, biosphere). Key terms: ecosystem, community, population, biosphere, habitat, niche. Practice Question: Explain the difference between a habitat and a niche.

• Energy Flow in Ecosystems: Understand how energy flows through an ecosystem, from producers to consumers to decomposers. Key terms: producer, consumer, decomposer, food chain, food web, trophic level. Practice Question: Describe the flow of energy through a typical food chain.

• Nutrient Cycles: Understand the cycling of important nutrients, such as carbon, nitrogen, and water, through ecosystems. Key terms: carbon cycle, nitrogen cycle, water cycle. Practice Question: Explain the role of decomposers in nutrient cycling.

• Population Dynamics: Understand factors that affect population size and growth, including birth rate, death rate, immigration, emigration, carrying capacity, and limiting factors. Key terms: population growth, carrying capacity, limiting factors, exponential growth, logistic growth. Practice Question: Explain the concept of carrying capacity.

IV. Test-Taking Strategies

Preparing for the 6.04 semester test is not just about memorizing facts; it's about understanding concepts and applying them to new situations.

• Review Regularly: Don't cram! Review the material regularly throughout the semester, focusing on areas where you feel less confident.

• Practice Problems: Work through practice problems and past test questions to familiarize yourself with the format and types of questions you'll encounter.

• Identify Weak Areas: Focus on your weak areas and seek clarification from your teacher or tutor.

• Time Management: Practice managing your time effectively during the test.

This comprehensive review should help you prepare thoroughly for your 6.04 Biology semester test, Part 1. Remember to utilize your class notes, textbook, and any additional resources your teacher provides. Good luck!