به انگلیسی

Chromosomes, Genes and DNA

Science · Ecosystems & Habitats · ages 12-13

Name ______________________ Date ____________

What do many genes provide instructions for?
- Making proteins that carry out jobs in cells
- Making membranes that wrap DNA into every gene
- Making muscles that pump blood on their own
Which statement correctly links a gene, DNA and a chromosome?
- DNA is a section of a gene within a chromosome.
- A chromosome is a section of DNA within a gene.
- A gene is a section of DNA within a chromosome.
Every human body cell has 46 chromosomes.
Circle one: True False
One DNA strand has the base sequence GCAT. Which sequence pairs with it at the corresponding positions?
- GCAT, using G-G and A-A pairs
- CGTA, using G-C and A-T pairs
- ATGC, using G-A and C-T pairs
An imagined organism's body cell has 7 pairs of chromosomes. How many chromosomes is that in total?
Answer: ______________
In a typical human skin cell, where are the chromosomes found?
- Embedded in the cell's outer membrane
- Inside the skin cell's nucleus
- Outside the cell
Which account correctly separates the scientists' roles in working out DNA's structure?
- Franklin and Wilkins studied X-ray patterns; Watson and Crick proposed the model.
- Watson and Crick studied X-ray patterns; Franklin and Wilkins proposed the model.
- Franklin and Crick studied X-ray patterns; Watson and Wilkins proposed the model.
Ben says, "Every trait is controlled by exactly one gene." Which statement corrects his claim?
- Traits depend only on the environment.
- Traits always depend on one gene and never on the environment.
- Traits can depend on several genes and the environment.

Answer key

For grown-ups. Fold this page away before handing over the rest.

Chromosomes, Genes and DNA W1-mt_6aJUzBYGNs-s1

Making proteins that carry out jobs in cells · Many genes provide instructions for proteins. Those proteins can build structures or carry out jobs in cells.
A gene is a section of DNA within a chromosome. · A gene is a section of DNA. A chromosome contains that DNA packaged with proteins, so a gene does not contain a chromosome.
False · 46 is the usual count for human body cells with nuclei. Mature red blood cells have no nucleus and no chromosomes, so 'every' is not accurate.
CGTA, using G-C and A-T pairs · Apply the pairing rule at each position: G pairs with C, C with G, A with T and T with A. The matching sequence is CGTA.
14 · Each pair contains two chromosomes. Multiply 7 by 2 to get 14 chromosomes.
Inside the skin cell's nucleus · The skin cell's nuclear chromosomes are inside its nucleus. They are neither embedded in the outer cell membrane nor outside the cell.
Franklin and Wilkins studied X-ray patterns; Watson and Crick proposed the model. · Franklin and Wilkins carried out X-ray studies. Watson and Crick used X-ray evidence and other researchers' findings to propose the double helix model.
Traits can depend on several genes and the environment. · A gene is not the same as a trait. Several genes and environmental effects can contribute to one trait.