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Biology Basics flashcards
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1
Question
What is DNA?
Page 1
Answer
DNA is a molecule that holds the instructions for how living things develop and function.
2
Question
What is a gene?
Page 1
Answer
A gene is a section of DNA that gives instructions to make a protein.
3
Question
What are chromosomes?
Page 1
Answer
Chromosomes are long, coiled strands of DNA and proteins that hold many genes.
4
Question
What are the four bases in DNA?
Page 1
Answer
The four bases in DNA are adenine (A), thymine (T), guanine (G), and cytosine (C).
5
Question
How do bases pair in DNA?
Page 1
Answer
Adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C).
6
Question
What is the purpose of mitosis?
Page 1
Answer
Mitosis makes body cells for growth and repair, producing identical cells.
7
Question
What is the purpose of meiosis?
Page 1
Answer
Meiosis makes sex cells (sperm and egg) with half the number of chromosomes, allowing genetic variety and ensuring offspring get the correct number.
8
Question
How many chromosomes do human sperm and egg cells each have?
Page 1
Answer
Human sperm and egg cells each have 23 chromosomes.
9
Question
What happens when sperm and egg join in fertilization?
Page 1
Answer
They form a zygote with a complete set of 46 chromosomes, 23 from each parent.
10
Question
How many chromosomes do humans have in total?
Page 1
Answer
Humans have 46 chromosomes.
11
Question
What are mutations in body (somatic) cells?
Page 1
Answer
Mutations in body cells are not passed to offspring.
12
Question
What are mutations in sex cells?
Page 1
Answer
Mutations in sex cells can be passed on, leading to genetic variation.
13
Question
What is natural selection?
Page 2
Answer
Natural selection happens when individuals with traits better suited to their environment survive and have more offspring, making those traits more common over time and changing the species.
14
Question
What is the role of variation in evolution?
Page 2
Answer
Variation means individuals are different from one another; without it, evolution can't happen because all would react the same way to changes.
15
Question
What is artificial selection?
Page 2
Answer
In artificial selection, humans choose which organisms breed for certain traits, differing from natural selection which happens without human control.
16
Question
Give an example of artificial selection.
Page 2
Answer
Breeding dairy cows so they make more milk; the goal is cows that produce higher milk yields.
17
Question
How can artificial selection affect genetic diversity?
Page 2
Answer
Artificial selection can lower genetic diversity, making populations weaker against disease or environmental change.
18
Question
What is extinction?
Page 2
Answer
Extinction is when a species disappears everywhere.
19
Question
What is extirpation?
Page 2
Answer
Extirpation is when a species disappears from one area but still exists somewhere else.
20
Question
Name three human activities that harm biodiversity.
Page 2
Answer
Habitat destruction (e.g., cutting down forests), pollution (e.g., plastics, pesticides), over hunting and overfishing.
21
Question
What are indicator species?
Page 3
Answer
Indicator species show if an ecosystem is healthy.
22
Question
Why are large carnivores often used as indicator species?
Page 3
Answer
Large carnivores often serve as indicators because they need large, healthy habitats.
23
Question
What is the Sixth Extinction?
Page 3
Answer
The current, human-caused mass extinction event where species are disappearing much faster than normal.
24
Question
How does biodiversity affect ecosystem recovery after disasters?
Page 3
Answer
Ecosystems with high biodiversity recover faster after disasters; fewer species (low biodiversity) means slower or incomplete recovery.
25
Question
Why does biodiversity recovery take time?
Page 3
Answer
Lost species may never come back; ecosystems need time, sometimes generations, to heal.
26
Question
What is the best way to protect ecosystems?
Page 3
Answer
It's best to protect entire habitats—not just individual species—to keep ecosystems balanced.
27
Question
What is the purpose of zoos in biodiversity protection?
Page 3
Answer
Zoos protect animals through breeding programs.
28
Question
What is a limitation of zoos?
Page 3
Answer
Zoos can't fully preserve natural behavior or total diversity.
29
Question
What is the purpose of seed banks?
Page 3
Answer
Seed banks store plant seeds for the future.
30
Question
What is a limitation of seed banks?
Page 3
Answer
Plants may not adapt well if the environment changes.