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Science > Unit 1 Cells > Flashcards

Unit 1 Cells Flashcards

Chapter 1 - Why is the reproduction of cells important?

1
Q

What are the main reasons reproduction is important?

A

Reproduction ensures:
1. Sustainability: Environment and species can endure.
2. Continuity: Species can exist over generations.

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2
Q

What is DNA, and why is it important in reproduction?

A

DNA (Deoxyribonucleic Acid) is the molecule of life that:
1. Stores genetic information.
2. Determines traits, functions, and behaviour of an organism.
3. Passes genetic material to offspring during reproduction.

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3
Q

What is the structure of DNA?

A

DNA is a double-helix made of four nucleotides:

Adenine (A) pairs with Thymine (T).
Cytosine (C) pairs with Guanine (G).

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4
Q

What are the differences between asexual and sexual reproduction?

A
  1. Asexual: One parent, offspring are identical.
  2. Sexual: Two parents, offspring are genetically diverse.
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5
Q

How do organisms reproduce asexually?

A
  1. Bacteria: Binary fission.
  2. Yeast: Budding.
  3. Mold: Spores.
  4. Plants: Vegetative propagation (e.g., potatoes).
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6
Q

How do bacteria reproduce?

A

Bacteria reproduce by binary fission, splitting into two identical daughter cells.

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7
Q

How do yeast reproduce?

A

Yeast reproduce asexually by budding, where a small bud grows on the parent and detaches.

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8
Q

How do moulds reproduce?

A

Moulds reproduce asexually by releasing spores from a structure called sporagium, which grow in favourable conditions such as warmth and moist and divde through mitosis and cytokinesis

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9
Q

How do plants reproduce asexually?

A

Plants reproduce through vegetative propagation, where new plants grow from roots, stems, or leaves.

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10
Q

What is the role of the cell cycle in eukaryotic cell reproduction?

A

The cell cycle allows cells to:
1. Replace old or damaged cells.
2. Produce new offspring in single-celled organisms.

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11
Q

What are the stages of mitosis?

A

PMAT:

  1. Prophase: Nuclear membrane disappears, chromosomes form.
  2. Metaphase: Chromosomes line up in the middle.
  3. Anaphase: Chromosomes separate to opposite ends.
  4. Telophase: Two nuclei form.
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12
Q

How does meiosis differ from mitosis?

A

Meiosis creates:

  1. Four haploid gametes (sex cells).
  2. Genetic variation through crossing over and independent assortment
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13
Q

What are gametes, and how are they formed?

A

Gametes are sex cells (sperm and egg) formed through meiosis, each with half the chromosomes of the parent.

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14
Q

What happens after fertilization in humans?

A
  1. Zygote divides via mitosis.
  2. Embryo implants in the uterus.
  3. Development occurs over 38 weeks (8 weeks embryonic, 30 weeks fetal)
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15
Q

What are the pros and cons of asexual reproduction?

A

Advantages:
Fast, requires one parent, many offspring.

Disadvantages:
Lack of genetic diversity; vulnerable to environmental changes.

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16
Q

What are the pros and cons of sexual reproduction?

A

Advantages:
Genetic variation increases survival in changing environments.

Disadvantages:
Slower process, requires two parents, fewer offspring.

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17
Q

How does sexual reproduction create genetic diversity?

A
  1. Crossing Over: Exchange of genetic material during Prophase I of meiosis.
  2. Independent Assortment: Random alignment of chromosomes during Metaphase I.
18
Q

What are some examples of sexual reproduction?

A
  1. Mammals: Internal fertilization, offspring develop inside females.
  2. Insects: Fertilization produces males or females (e.g., bees).
  3. Fungi: (yeasts/moulds) - reproduce asexual and sexual
  4. Fish, Frogs, and Birds: fertilized eggs develop outside the female
  5. Plants: Pollination produces seeds.
19
Q

How does asexual and sexual
reproduction contribute to life on Earth?

A
  1. Asexual Reproduction: Produces many identical offspring quickly.
  2. Sexual Reproduction: Introduces genetic diversity, ensuring survival in changing environments.
20
Q

How does reproduction relate to sustainability?

A

Sustainability is the ability of an environment and the species it supports to endure over time. Reproduction ensures species can continue contributing to interconnected ecosystems.

21
Q

Why is reproduction important for continuity?

A

Continuity means the ongoing existence of a species over generations, which is only possible through reproduction.

22
Q

What is the difference between chromatin and chromosomes?

A

Chromatin: Coiled DNA within the nucleus.

Chromosomes: Condensed chromatin that forms before reproduction, carrying genetic material to offspring.

23
Q

Describe binary fission in detail.

A
  1. The parent cell duplicates its DNA.
  2. The cell elongates, pulling the DNA copies apart.
  3. The cell splits into two identical daughter cells.
24
Q

How does budding work in yeast?

A

A small growth (bud) forms on the parent cell, grows, and detaches to form a new, smaller cell that eventually grows to full size.

25
Q

What happens during spore formation in mould?

A

Mould releases spores from a sporangium. When spores land in a warm, moist environment, they divide by mitosis and grow into new mould.

26
Q

What happens during interphase?

A

The cell grows, increases organelles, and duplicates its DNA to prepare for division

27
Q

What is cytokinesis?

A

Cytokinesis is the final stage of cell division, where the cytoplasm and organelles divide to form two separate cells.

28
Q

What is crossing over, and why is it important?

A

Crossing over occurs in Prophase I of meiosis when homologous chromosomes exchange genetic material, increasing genetic variation.

29
Q

How does independent assortment occur?

A

During Metaphase I, homologous chromosome pairs align randomly, creating unique combinations of chromosomes in gametes.

30
Q

What is the difference between haploid and diploid cells?

A

Diploid Cells: Contain two sets of chromosomes (e.g., body cells).

Haploid Cells: Contain one set of chromosomes (e.g., gametes).

31
Q

What happens during fertilization?

A

A sperm cell and egg cell combine to form a zygote, restoring the diploid chromosome number and beginning the development of a new organism.

32
Q

Why is asexual reproduction beneficial?

A
  1. Requires one parent.
  2. Rapid reproduction and population growth.
  3. Offspring mature quickly.
33
Q

What are the disadvantages of asexual reproduction?

A
  1. Lack of genetic diversity.
  2. Vulnerability to environmental changes (e.g., disease, drought).
34
Q

Why is sexual reproduction beneficial?

A
  1. Creates genetic diversity.
  2. Improves survival chances in changing environments.
35
Q

What are the disadvantages of sexual reproduction?

A
  1. Slower process with fewer offspring.
  2. Requires energy to find a mate and care for young.
36
Q

How is DNA stored in cells, and what happens during reproduction?

A

DNA is stored in the nucleus as chromatin, a coiled form that fits into the cell.

Before reproduction, chromatin condenses further into chromosomes.

Chromosomes are duplicated and transferred to offspring during reproduction.

37
Q

What role do chromosomes play in reproduction?

A

Chromosomes carry DNA, the genetic blueprint of an organism. During reproduction, chromosomes are copied and passed to offspring, ensuring the transfer of genetic information.

38
Q

How does reproduction differ between prokaryotic and eukaryotic cells?

A

Prokaryotic Cells: Reproduce through binary fission (e.g., bacteria).

Eukaryotic Cells: Reproduce through the cell cycle, which includes mitosis and cytokinesis.

39
Q

How do mammals reproduce sexually?

A

Mammals use internal fertilization, where the sperm fertilizes the egg inside the female body.

The zygote develops into an embryo and then into a fetus, receiving nourishment from the mother.

40
Q

Why is genetic variation important for survival?

A

Genetic variation allows some individuals to adapt better to environmental changes.

Increases the likelihood of species survival during diseases, climate changes, or resource scarcity.

Science (4 decks)

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