BC SCIENCE 10 · BIOLOGY
Visual, ELL-friendly lessons based on the MOSAIC Biology worksheet. Read the material directly on the website, then open the printable PDF whenever you need it.
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Big Question: How does DNA help explain why living things are different?
| Vocab | What it means |
|---|---|
| Variation | The presence of differences in characteristics |
Living things are different. Some fly. Some jump. Some grow leaves. Some are microscopic(small). These differences are called variation. Many variations are linked to DNA.
DNA as instructions DNA is inside every cell DNA is like an instruction book *A T C G These letters are instructions for making proteins Cells read the instructions and make proteins (Proteins do the work) → It leads to traits (what we see)
| Vocab | What it means |
|---|---|
| DNA | instruction inside cells |
| Trait | a feature of a living thing |
| Variation | differences between living things |
| Organism | a living thing |
DNA is like an instruction book. It gives cells information. Cells use this information to build and run living things. DNA can affect traits. *Different DNA letters → Different proteins → Different traits
*Change in just one letter (in DNA) can change the trait Why? : Different DNA → Different proteins → Different traits
Organisms in the same group can still be different. Plants are not all the same. Animals are not all the same. Tiny organisms are not all the same. DNA helps create many of these differences.
DNA is made of small pieces. Each piece is called a nucleotide. A nucleotide has: 1. phosphate 2. sugar 3. base The bases are DNA letters. They are: A, T, C, G
DNA has only 4 letters The order of these letters is the recipe Different recipes (orders) lead to different traits
| Vocab | What it means |
|---|---|
| Complementary base pairing | A pairs with T, C pairs with G |
DNA bases pair in a specific way. A pairs with T. C pairs with G. This is called complementary base pairing. It is like puzzle pieces. Only the correct pieces fit.
DNA has two strands. It looks like a twisted ladder. The sides are made of sugar and phosphate. The steps are base pairs. A—T C—G
| Vocab | What it means |
|---|---|
| Chromosome(s) | Packed DNA |
DNA is very long. Cells are very small. So DNA must be packed. Packed DNA forms chromosomes.
DNA Chromatin Chromosome Long DNA DNA wraps around histones Chromatin fibre (Compacted DNA) Tightly packed DNA *DNA is packed step by step to fit inside the cell
DNA can be loose. Loose DNA is called chromatin. Before cell division, DNA packs tightly. Tightly packed DNA is called a chromosome.
Cell Division (1)DNA packs (2)Chromosomes form (3)Cell divides (4)New cells get DNA
Cells divide to make new cells. Before cell division, DNA must be organized. Chromosomes help DNA move correctly into new cells. This connects to mitosis and meiosis (later)
Human body cells usually have chromosome pairs. One chromosome in a pair comes from the biological mother. One chromosome in a pair comes from the biological father. Pairs help explain inheritance. Inheritance means traits can pass from parents to offspring.
| Vocab | What it means |
|---|---|
| Gene | a section of DNA |
| Allele | a version of a gene |
Homologous chromosomes are a pair. They are similar. They have the same genes in the same places. But they may have different alleles. So they are not exact copies.
DNA stores instructions. Nucleotides build DNA. Base pairs help DNA keep its order. DNA packs into chromosomes. Chromosomes contain genes. Genes can have different alleles. This helps explain variation.
Big Question: How is genetic information passed on and shown in living things?
| Vocab | What it means |
|---|---|
| DNA replication | Before a cell divides, DNA must copy itself |
| Replication | making a copy |
Before a cell divides, DNA must copy itself. This is called DNA replication. Replication means making a copy. One DNA molecule becomes two DNA molecules. Each new cell needs DNA instructions.
DNA Zipper Copy Original DNA (Before copying) 1. the strands separate (like a zipper opening) 2. New strands are built by matching bases (old line + new line = DNA 1) (old line + new line = DNA 2) 3. Two identical DNA molecules are created! → DNA 1 = DNA 2
DNA has two strands. The strands separate. Each old strand becomes a guide. New bases match the old bases. A pairs with T. C pairs with G. This creates two DNA molecules.
Why DNA copying matters 1. DNA copies DNA is copied so each new cell has the instructions it needs 2. Chromosomes form The copied DNA packs into chromosomes and gets organized 3. Cell divides The cell separates into two new cells. Chromosome are pulled apart 4. New cells receive DNA Each new cell gets a complete set of chromosomes and DNA
Each new cell receives DNA. That is why DNA structure is important. It helps genetic information pass on correctly.
DNA stores instructions. A cell can make an RNA copy of one gene. The RNA copy helps make a protein. Proteins help cells work. Proteins can affect traits.
DNA does not directly make traits. DNA gives instructions. Cells use the instructions to make proteins. Proteins help create body features and cell functions.
| Vocab | What it means |
|---|---|
| Genetic diversity | differences in genes within a species |
| Species diversity | different species living in one area |
| Ecosystem diversity | different ecosystems exist on Earth |
Biodiversity means the variety of life. It has different levels.
Members of the same species can still be different. They may have different inherited traits. Example: Humpback whales can have different tail patterns. This is genetic diversity. Genetic diversity helps populations survive changes.
Species diversity means many different species live in an area. A wetland can have: birds fish frogs plants insects bacteria More species can make an ecosystem stronger.
Ecosystem diversity means Earth has many kinds of ecosystems. Different ecosystems have different conditions. Examples: temperature water light soil food Different conditions support different organisms.
| Vocab | What it means |
|---|---|
| genetics | study of heredity |
| heredity | passing traits from parents to offspring |
| offspring | child or new organism |
Offspring often look similar to their parents. This happens because parents pass on genes. This is called heredity. Heredity means traits pass from parents to offspring.
Gregor Mendel studied pea plants. He looked at traits like flower colour. He crossed purple-flowered plants with white-flowered plants. In the first generation, the flowers were purple. Later, white flowers appeared again. This showed that traits can be hidden and reappear.
Dominant Allele (strong allele) B = Loud button Recessive Allele b = Quiet button BB Two loud buttons → Loud trait shown Bb One loud, one quiet → Loud trait shown (B is stronger than b) (Dominant allele is stronger than recessive allele) bb Two quiet buttons → Quiet trait shown
An allele is a version of a gene. Some alleles are dominant. A dominant allele shows its trait if it is present. Some alleles are recessive. A recessive trait shows only when there are two recessive alleles.
| Vocab | What it means |
|---|---|
| Genotype | the allele combination (alphabet/letters) |
| Phenotype | the trait we can see (explanation) |
Genotype Examples: BB Bb bb Phenotype means the trait we can see. Examples: purple flower white flower
| Vocab | What it means |
|---|---|
| Homozygous | two alleles are the same |
| Heterozygous | two alleles are different |
Homozygous means two alleles are the same. BB is homozygous. bb is homozygous. Heterozygous means two alleles are different. Bb is heterozygous.
Dominant does not always mean common. Dominant does not always mean better. Some traits are controlled by one gene. But many human traits are controlled by many genes. Environment can also affect traits.
DNA can copy itself. Genes are sections of DNA. Parents pass genes to offspring. Alleles are versions of genes. Alleles affect traits. Different traits create variation. Variation helps create biodiversity.
Big Question: How is genetic information passed on, and how can populations change over time?
| Vocab | What it means |
|---|---|
| chance | the coin can land on heads or tails |
| allele | different versions of a gene |
| probability | we can use the coinflip to predict the chance of different traits |
Probability means chance. A coin flip has two possible results. Heads or tails. Alleles also have possible combinations. A Punnett square helps predict those combinations.
A Punnett square is a prediction tool. It shows possible allele combinations. The top (purple letters) shows alleles from one parent. The side (green letters) shows alleles from the other parent.
Step 1: Draw a box with four squares. Step 2: Write one parent’s alleles (letters) on top. Step 3: Write the other parent’s alleles (letters) on the side. Step 4: Combine the letters in each square. Each square is one possible genotype.
B = black hair allele. b = red hair allele. B is dominant. b is recessive. Bb shows black hair. bb shows red hair. This cross predicts: 50% Bb 50% bb So half may show black hair.
| Vocab | What it means |
|---|---|
| Dominance | Only one alleles are expressed BB → B (loud) Bb → B (loud) bb → b (quiet) |
| Codominance | Both alleles are expressed RR → R (red) WW → W (white) RW → RW (red + white at the same time) |
In codominance, both alleles show. One allele does not hide the other.
Red hair allele + white hair allele Both red and white hairs appear. This can make a roan animal.
Blood type is controlled by alleles. A and B are codominant. That means both can show together. Type AB shows both A and B. O is recessive. Type O appears when the genotype is ii.
| Vocab | What it means |
|---|---|
| Incomplete dominance | neither allele fully dominates *Both alleles are not strong enough to be alone when they are together → they get mixed |
In incomplete dominance, neither allele fully hides the other. The heterozygous trait is in between. Example: Red flower × white flower → The offspring can be pink. → Pink is the blended phenotype.
Pattern What happens? Heterozygous Example Dominance one allele hides another Bb = loud (one trait) Codominance both alleles show AB blood (two traits at the ame time) Incomplete dominance alleles blend RW = pink (two traits mixed)
| Vocab | What it means |
|---|---|
| sex-linked traits | some genes found on sex chromosomes |
| Males | X and Y chromosome |
| Females | X and X chromosome |
Many sex-linked traits are on the X chromosome. Males usually have one X and one Y. Females usually have two X chromosomes. Because males have only one X, recessive X-linked traits can show more often in males.
Some people have difficulty seeing red and green as different colours. This can be caused by an X-linked recessive allele. A male with the recessive allele on his X chromosome will show the trait. Red-green colour vision deficiency as X-linked recessive trait. A male with the recessive allele on his X chromosome will show the trait. A female may be a carrier if one X has the allele and the other X does not.
| Vocab | What it means |
|---|---|
| Mutation | permanent change in DNA |
A mutation is a change in DNA. Sometimes the change is small. Sometimes it can affect a trait. Mutations can happen when DNA is copied. Mutations can also be caused by environmental factors.
Not all mutations are harmful. Some are harmful. Some have no effect. Some can be helpful.
Members of the same species can look different. This is genetic variation. Mutations can create new alleles. New alleles can add variation to a population. Variation is important for natural selection. → Mutation creates new alleles and variation in a population.
Environment Natural Selection ⇒ Over time, the environment “selects” for shade-tolerant trees Selective pressure it affects an organism’s ability to survive and reproduce environment change : More sunlight → dense shade Survival staying alive shade-tolerant trees survive sun-loving trees struggle Reproduce create new offsprings shade-tolerant trees reproduce more
| Vocab | What it means |
|---|---|
| Selective advantage | a helpful trait |
| Natural selection | Nature favours traits that help survival / reproduction in an environment |
Natural selection happens when some traits help organisms survive. A helpful trait is called a selective advantage. Organisms with helpful traits are more likely to survive. They are more likely to reproduce. Their alleles can become more common over generations.
Natural selection acts on populations, not just one individual.
Mutation Antibiotic Survive Reproduce green bacteria become purple bacteria - medicine (killing bacteria) is injected - medicine removes green bacteria purple bacteria survived from the medicine purple bacteria reproduce (make more offsprings)
Some bacteria may have a mutation. The mutation can make them resistant to an antibiotic (medicine). When antibiotics are used, non-resistant bacteria die. Resistant bacteria survive. They reproduce quickly. Over time, the population changes.
Same trait - dark color Helpful here Dark color is helpful to hide because the tree (environment) is also dark Not helpful here Dark color is not helpful here to hide because the tree (environment) is white The color makes it easier to be detected by birds (predator)
A trait can be helpful in one environment but not helpful in another. Natural selection has no plan. It depends on the environment. A trait can be helpful in one place. The same trait may not help in another place.
| Vocab | What it means |
|---|---|
| Adaptation | structure/behaviour/process that helps survival and reproduction |
Adaptations can be: body structures behaviours body processes Examples: Bird beaks help birds eat certain food. Thick fur helps animals stay warm. Cactus spines help protect the plant.
Separated population Different environment New species One bird population splits onto different islands Each island has different food sources Each island has different environments and food Over many generations, beaks change to better fit the available food. Eventually, the populations become so different that new species form. The birds can no longer interbreed. They are now different species.
| Vocab | What it means |
|---|---|
| Speciation | Because of different environments, populations can become very different and become new species over many generations |
A species is a group that can reproduce and have fertile offspring. Sometimes populations become separated.
Over many generations, populations can become very different. They may become new species. This is called speciation (When populations become separated and change over time, new species form)
| Vocab | What it means |
|---|---|
| Adaptive Radiation | It happens when one ancestral species becomes many species |
This often happens when organisms move into different environments. Different environments favour different traits. Example: Galapagos finches have different beak shapes. Different beaks help them eat different foods.
| Vocab | What it means |
|---|---|
| Extinction | when a species disappears from Earth |
Selective pressure can help new species form. But it can also lead to extinction. If a population cannot survive a changed environment (selective pressure), it may die out.
| Vocab | What it means |
|---|---|
| Mutagen | something that increases the chance of mutation |
| Carcinogen | something that can cause cancer |
Examples: UV radiation X-rays some chemicals Some mutagens are carcinogens. A carcinogen is something that can cause cancer. UV radiation can increase the risk of skin cancer. Sunscreen and shade can reduce UV exposure.
Genes are passed from parents to offspring. Alleles affect traits. Punnett squares predict possible offspring genotypes. Mutations create new alleles. New alleles create variation. Natural selection acts on variation. Over time, populations can change. Sometimes new species form. Sometimes species go extinct.
Big Question: How can DNA technology be used, and what questions can it raise?
| Vocab | What it means |
|---|---|
| Biotechnology | Using living things or DNA technology to make useful products |
Utilizing biotechnology, scientists can: copy DNA change DNA move DNA into another organism This can help with food, medicine, farming, and disease testing.
| Vocab | What it means |
|---|---|
| Gene cloning | Copying a gene many times |
| Gene | A section of DNA |
Gene cloning means copying a gene many times. A gene is a section of DNA. Scientists can place a gene into bacteria. The bacteria can copy the gene. Sometimes bacteria can also make a useful protein. Example: A copied insulin gene can help make insulin.
| Vocab | What it means |
|---|---|
| Recombinant DNA | DNA made from different sources |
Recombinant DNA is DNA made from different sources. Think of it like combining puzzle pieces. One DNA piece can be joined with another DNA piece. This can create DNA with a new instruction.
The visual above shows a transgenic organism resisting to harmful insects.
| Vocab | What it means |
|---|---|
| Transgenic organism | DNA from another organism |
| Carcinogen | something that can cause cancer |
A transgenic organism has DNA from another organism. Scientists add a useful gene. That gene can give the organism a new trait. Example: A plant may get a gene that helps it resist insects.
| Vocab | What it means |
|---|---|
| Golden rice | Rice changed to add more nutrition (vitamin A) after genetic modification |
Some plants are genetically modified. Golden rice is rice changed to add more nutrition. It can help provide vitamin A. This is an example of using DNA technology for food and health.
Some crops are changed to resist insects. This can protect crops. It can help farmers grow more food. But scientists also need to study possible effects on ecosystems.
Some animals can be genetically modified. They may produce useful proteins. Example: A goat can produce a medical protein in its milk. This protein may be used for medicine.
DNA technology has many uses. It can help: identify DNA samples study disease test food crops help some people have children detect invasive species
| Vocab | What it means |
|---|---|
| Gene therapy | treatment of genetic disorders by adding a healthy gene and letting it help cells make a normal protein |
Gene therapy tries to treat genetic disorders. The goal is to add a healthy gene. The healthy gene may help cells make a normal protein. This technology is still carefully studied.
DNA technology can help British Columbia. Scientists can test plants and forests. They can look for: plant viruses invasive species forest pathogens Early detection can reduce damage.
Biotechnology can be useful. But it can also raise questions. People may ask: Is it safe for the environment? Is it safe for health? Who controls the technology? Is it fair? Should animals be used this way? There is not always one simple answer. \
Biotechnology uses DNA and living organisms. Scientists can copy, change, or move genes. This can create useful products. It can help with farming, medicine, and testing. But every use should be checked for safety, ethics, and environmental effects.
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