Week 3: Week 3 Content
Grade 7 Science | Rosche | Kairos Academies
**Scientists Like Us:** In this lesson, you'll work as a team of scientists investigating [topic-specific content]. Every scientist brings unique perspectivesโyour ideas matter!
**Community Connection:** This phenomenon affects our community in [topic-specific content]. You'll investigate how scientists use evidence to understand [topic-specific content] in places like ours.
**Progress Checkpoint:** You've completed [topic-specific content]. Next up: [topic-specific content].
**Pair-Share:** First, think about [topic-specific content] on your own (1 min). Then share with your partner (2 min). Finally, we'll discuss as a class.
Accessibility & Learning Support
- Need text read aloud? Chrome: Right-click then "Read aloud" | Edge: Click speaker icon in address bar
- Working from home? Look for the HOME ALTERNATIVE boxes at each station
- Need extra support? Click the green "Need help?" buttons for hints and sentence starters
- Stuck? Look for the red "Stuck?" boxes with step-by-step help
NGSS Standards Covered This Week
MS-LS1-4 (Primary)
What it means: Use argument based on empirical evidence and scientific reasoning to support an explanation for how characteristic animal behaviors and specialized plant structures affect the probability of successful reproduction.
Connection to this week: Gene expression drives specialized behaviors and structures that help organisms survive and reproduce.
MS-LS1-8 (Primary)
What it means: Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate behavior or storage as memories.
Connection to this week: Cell signaling pathways allow sensory information to trigger gene expression and cellular responses.
3-Dimensional Learning
| Dimension | What You'll Practice |
|---|---|
| SEP-2 Developing & Using Models | Model gene expression and cell signaling pathways |
| DCI LS1.A & LS1.B | Structure/function + growth/development via gene expression |
| CCC-2 Cause & Effect | Signals cause gene expression changes, which affect cell type |
Success Criteria - How You'll Know You've Got It
Target 1: Explain what gene expression is and how signals control it
Self-check: Can I explain how a chemical signal turns genes "on" or "off"?
Target 2: Trace the path of a signal from outside the cell to the nucleus
Self-check: Can I describe the signal pathway: cell membrane โ cytoplasm โ nucleus โ gene activation?
Target 3: Explain how different signals activate different genes
Self-check: Can I explain why insulin signals turn on different genes than growth signals?
Why This Matters to YOU:
Your body sends trillions of chemical signals every second! Adrenaline tells your heart to beat faster, insulin tells muscles to absorb sugar, and growth factors tell skin to heal. Cell communication coordinates your 37 trillion cells to keep you alive.
WORKED EXAMPLE: Insulin Signaling Breakdown (Week 3 - Minimal Scaffolding)
Week 3 challenge: YOU work through most steps independently!
PROBLEM:
Sarah's doctor says her body makes insulin, but her cells don't respond to it (Type 2 diabetes). Her blood sugar stays high even when insulin is present. After eating lunch, her blood sugar is 180 mg/dL (should be 100 mg/dL). Using your Week 1-3 knowledge, trace where the signal pathway is breaking down and propose what cellular structure might be damaged.
YOUR TURN - Minimal Scaffolding:
- Map the NORMAL pathway: Where does insulin go after pancreas releases it? What happens at each step?
- Identify the breakdown point: If insulin reaches cells but they don't respond, what part of the pathway is failing?
- Connect to Week 2: What organelles are involved in processing this signal once it enters the cell?
- Predict treatment: Should Sarah take more insulin, or fix the receptors? Justify your answer using the signal pathway.
Vocabulary
Cognate Strategy: Many science words look similar in English and Spanish โ use your Spanish to learn science!
| Term | Spanish | Definition |
|---|---|---|
| gene expression | expresiรณn de genes | Process of turning genes "on" to make proteins |
| receptor | โ | receptor |
| hormone | โ | hormona |
| insulin | โ | insulina |
| nucleus | nรบcleo | Cell organelle containing DNA; signal target for gene activation |
| signal | seรฑal | Chemical message sent between cells to coordinate responses |
| pathway | vรญa / camino | Route a signal takes from cell membrane to nucleus |
Worked Example
Step-by-Step Problem Solving
Problem Scenario
Review the problem scenario and work through each step below.
YOUR CHOICE: Select Your Cell Communication Strategy
You're designing an immune response system for detecting viruses. YOU choose which signaling philosophy aligns with YOUR values!
Path A: Broad Alert System
Strategy: Send ONE universal "danger" signal to ALL cells when virus detected. Every cell responds immediately. If you value speed and simplicity, choose this path.
Trade-offs: Fast response but wastes energy (skin cells responding to lung virus). Can cause inflammation in healthy tissues.
Path B: Targeted Signal Cascade
Strategy: Detector cells send Signal 1 โ activates nearby defenders who send Signal 2 โ activates memory cells. Three specialized signals for three cell types. If you value precision and efficiency, choose this path.
Trade-offs: More precise, less collateral damage, but slower (signals must cascade). Complex system can have more failure points.
Path C: Adaptive Learning System
Strategy: First exposure sends broad signals (like Path A). Memory cells "learn" which signals worked best. Next time, send only optimized signals (like Path B). If you value improvement and adaptation, choose this path.
Trade-offs: Best long-term performance but requires time to "learn." First exposure is messy. Requires energy to maintain memory cells even when healthy.
The Phenomenon: The Cell's Instruction Manual
Imagine you have a cookbook with 20,000 recipes (your DNA has ~20,000 genes). But you're not making ALL 20,000 dishes at once!
- A pancreas cell "reads" the insulin recipe (turns on insulin genes)
- A skin cell "reads" the keratin recipe (turns on keratin genes)
- Both cells have the SAME cookbook (DNA), but they're reading DIFFERENT recipes!
- WHO decides which recipes to read? โ Chemical signals!
When blood sugar rises, a signal reaches the pancreas and says "Read the insulin recipe NOW!" The cell turns on insulin genes, makes insulin proteins, and releases them into blood. But how does this signal work?
Focus Question: How do cells know what job to do?
Learning Targets
By the end of this week, you will be able to:
Meet the Scientist: Barbara McClintock
Barbara McClintock was a pioneering geneticist who revolutionized our understanding of how genes work. Working with corn plants in the 1940s-1950s, she made a discovery that seemed impossible at the time: some genes could move around within the DNA - they weren't stuck in fixed positions! She called these "jumping genes" or transposons, a discovery so ahead of its time that most scientists didn't believe her until decades later. In 1983, at age 81, she won the Nobel Prize for this work.
The Discovery: McClintock noticed that corn kernels had unusual color patterns that changed from generation to generation in ways that didn't match regular inheritance rules. By carefully tracking these patterns over many years, she realized that some genetic elements could physically move to different locations on chromosomes. When a jumping gene moved near another gene, it could turn that gene on or off! This showed that gene expression wasn't just controlled by static chemicals - the genes themselves could move and rearrange.
Why This Matters: McClintock's jumping genes revealed that organisms could evolve and regulate genes in ways scientists never imagined. We now know that transposons make up about 45% of the human genome! They're crucial for evolution, because when genes move and create new combinations, they can produce beneficial new traits. Her work directly explains how gene expression is controlled - it's not just about signals turning genes on, but also about physical changes in DNA structure. This connects perfectly to Week 3's focus on how signals control gene expression!
Connection to Grade 7: This week you're learning how chemical signals control which genes are expressed. McClintock showed us that gene regulation is even more complex - genes can move and physically change how signals affect them. Her work proves that understanding cell communication requires understanding both chemistry AND genetics!
"In the long run, it is important that research be meaningful. It can be original, but need not be novel." - Barbara McClintock
Science in St. Louis: Genomics & Gene Research
Washington University School of Medicine and Siteman Cancer Center have world-class genomics labs studying gene expression in cancer cells, including McClintock's jumping genes. St. Louis researchers use CRISPR to edit genes and study cell signaling pathways controlling gene expressionโapplying McClintock's discoveries to modern medical research happening in your community.
Building on Weeks 1 & 2
| Previous Week | This Week's Extension |
|---|---|
| Week 1: All cells have nucleus (contains DNA) | Signals must reach the nucleus to turn genes on/off |
| Week 2: Different genes turned "on" in different cells | Chemical SIGNALS control WHICH genes turn on |
| Week 2: Cells specialize during development | Signals from nearby cells tell stem cells when to specialize |
Vocab
Key Vocabulary This Week (English | Espanol)
| English | Espanol | Cognate? | Student-Friendly Definition |
|---|---|---|---|
| gene expression | expresion de genes | Yes | When genes are turned "on" to make proteins |
| cell signal | senal celular | Yes | Chemical message sent between cells |
| receptor | receptor | Yes | Protein on cell membrane that "catches" signals |
| hormone | hormona | Yes | Chemical signal that travels through blood |
| insulin | insulina | Yes | Hormone signal that tells cells to absorb sugar |
| pathway | via/camino | - | The route a signal takes from cell membrane to nucleus |
Amazing! 5 out of 6 words (83%) are cognates! Science vocabulary often comes from Latin and Greek roots.
Practice These Vocabulary Terms
INTERACTIVE: Gene Expression Simulator
Send different chemical signals to a cell and watch how they activate different genes. Notice: the DNA stays THE SAME - only which genes are "read" changes!
BONUS: PhET Gene Expression Essentials
For deeper exploration, use this PhET simulation to see the molecular details of gene expression!
How to use the simulation (click to expand)
- Start with the "Expression" tab at the top
- Click "Positive Transcription Factor" and drag it to the cell
- Watch carefully: The transcription factor binds to DNA โ RNA polymerase starts making mRNA โ Ribosomes make protein!
- Try "Negative Transcription Factor" - What happens? (The gene stays OFF!)
- Switch to "Multiple Cells" tab - Try adding different concentrations of transcription factors to see how environment affects cell behavior
- Key insight: The SAME DNA can produce different proteins based on which genes are "turned on" by signals!
Remember: All cells in your body have the same DNA, but different signals activate different genes - that's how you get 200+ cell types!
Misconception Alert!
Cell specialization is NOT random luck! Chemical signals from nearby cells or the environment specifically tell cells which genes to turn on. This is a controlled, precise process - not a dice roll!
Need extra support? Click here for simulation tips
How to Use the Simulation:
- Start with an unspecialized cell (all genes OFF)
- Click a SIGNAL button to send a chemical message
- Watch which GENES turn ON (highlighted)
- Observe what PROTEINS are made
- See how the CELL CHANGES (shape, color, features)
Key Pattern:
Signal โ Nucleus โ Genes turn ON โ Proteins made โ Cell structure/function changes
Sentence Starters:
- "When Signal X reaches the cell, it causes..."
- "The DNA does not change, but..."
- "This shows that cell specialization is controlled by..."
Connecting to Week 2
Last week you learned that red blood cells have no nucleus but nerve cells have large nuclei. NOW you know WHY - different signals activated different genes during development, creating different cell structures!
COMPLETE THE STATION 1 FORM BELOW
Use the simulation to explore how signals control gene expression.
[EMBED G7.C1.W3 Station 1 Form Here]
Form ID: ________________
Learning Support Tracker
I do + You watch
We do together
You do + I check
Independent Practice:
Use the 5-step process from Weeks 1-2 to solve this on your own.
Apply the same structure-function reasoning you've practiced: identify the signal pathway, trace it from membrane to nucleus, explain which genes activate, and connect to the cellular response. Check your work against the rubric in the form.
You've got this! You've seen full examples (Week 1) and practiced with guided support (Week 2). Now demonstrate your independent mastery of cause-effect relationships in cell signaling.
Station 2 - Signal Analysis
20 Points | ~15 Minutes
Your Mission: Trace Cell Signaling Pathways
The Signal Pathway (4 Steps):
Step 1: Signal reaches cell membrane
Chemical signal (like insulin) binds to receptor protein on cell surface
Step 2: Signal travels to nucleus
Message is passed through cytoplasm via relay proteins
Step 3: Gene is turned ON
Signal reaches DNA, specific gene becomes active
Step 4: Protein is made
Active gene โ mRNA โ ribosomes make protein โ cell response!
Real Example: Blood Sugar Regulation
- You eat a meal โ blood sugar rises
- Pancreas detects high sugar โ releases insulin (signal)
- Insulin travels through blood to muscle/fat cells
- Insulin binds to receptors on cell membranes
- Signal pathway: membrane โ cytoplasm โ nucleus
- Genes for sugar absorption turn ON
- Proteins made that transport sugar INTO cells
- Blood sugar drops back to normal!
This is a FEEDBACK LOOP - the response (sugar absorbed) opposes the original change (high sugar).
Why Different Signals Activate Different Genes
Each signal has a unique SHAPE. Only cells with matching RECEPTORS can "catch" that signal. Then the signal activates its specific target genes. It's like a key (signal) that only fits certain locks (receptors)!
Need extra support? Click here for pathway help
Remembering the Pathway Order:
OUTSIDE โ Membrane (receptor catches signal) โ Cytoplasm (relay) โ Nucleus (gene activation) โ Ribosome (protein made) โ RESPONSE
Sentence Starters:
- "The insulin signal first reaches..."
- "After the signal reaches the nucleus, it causes..."
- "This is a feedback loop because the response..."
- "If cells don't respond to insulin signals, then..."
COMPLETE THE STATION 2 FORM BELOW
Analyze signal pathways and feedback loops.
[EMBED G7.C1.W3 Station 2 Form Here]
Form ID: ________________
Station 3 - Design a Cell Signal System
25 Points | ~20 Minutes (Highest Value!)
Engineering Challenge: Design a Communication System
The Challenge:
You're designing a communication system for a colony of cells that must work together. The cells need to:
- Coordinate to respond to threats (like bacteria invading)
- Different cells do different jobs (some detect, some attack, some remember)
- Signals reach the RIGHT cells without affecting the wrong ones
Your Design Must Include:
- Signal Types: How many different signals? What does each signal do?
- Recognition System: How do cells "know" which signals to respond to? (receptors!)
- Coordination Plan: When bacteria arrive, what sequence of signals coordinates the response?
- Signal Shutoff: How does the system turn OFF when threat is gone?
- Defense of Design: Why is your targeted system better than sending one signal to ALL cells?
Example Scenario: Bacteria Detection
- Cell Type A (detector cells) - have receptors for bacteria molecules, release Signal 1 when bacteria detected
- Signal 1 activates both Cell Type B and Cell Type C
- Cell Type B (attack cells) - have receptors for Signal 1, turn on genes for enzymes that destroy bacteria
- Cell Type C (memory cells) - have receptors for Signal 1, turn on genes to "remember" this bacteria type
- Feedback: When bacteria destroyed, Signal 1 production stops โ attack ends
Need extra support? Click here for design strategies
Design Strategy:
- Identify the PROBLEM - what needs to be coordinated?
- Define CELL TYPES - what jobs need doing?
- Create SIGNALS - one per major message type
- Match RECEPTORS - which cells should respond to which signals?
- Plan SEQUENCE - what order do signals activate?
Sentence Starters:
- "My system uses ___ different signals because..."
- "Cell Type A responds to Signal X because it has..."
- "When bacteria arrive, first Signal ___ activates..."
- "My targeted system is better than one universal signal because..."
COMPLETE THE STATION 3 FORM BELOW
Design your cell communication system!
[EMBED G7.C1.W3 Station 3 Form Here]
Form ID: ________________
Exit Ticket - Gene Expression Integration
23 Points | ~15 Minutes
Show What You Learned
Question Types:
- 2 NEW - Gene expression definition, insulin/pancreas example
- 2 SPIRAL - Week 2 (cell specialization), Week 1 (organelle pathway)
- 1 INTEGRATION - Connect signal โ nucleus โ gene โ protein pathway
- 1 SEP-1 - Generate scientific question about cancer/signals
Total: 6 questions, 23 points
Spiral Questions Increasing!
This week you'll have TWO spiral questions - one from Week 2 and one from Week 1. This helps you remember important concepts as we build new knowledge!
COMPLETE THE EXIT TICKET BELOW
This is your final assessment for Week 3. Take your time!
[EMBED G7.C1.W3 Exit Ticket Form Here]
Form ID: ________________
Enrichment & Extension
Optional deep dives for early finishers.
Optional content if you finish early or want to go deeper.
Scientist Spotlight
Research a scientist who contributed to this week's topic area and describe their key findings.
Environmental Justice Connection
Explore how this week's science concepts connect to environmental justice issues in our community.