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Science 9 > Chapter 2: Cell Growth and Reproduction > Flashcards

Chapter 2: Cell Growth and Reproduction Flashcards

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1
Q

What are the main functions of cell division?

A

Growth, repair and reproduction.

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2
Q

How is cell division responsible for growth?

A

After a cell reaches a certain size it stops functioning properly, so it must divide into 2 identical cells that perform the same function.

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2
Q

How is cell division responsible for repair?

A

Old cells are replaced with new ones after they die, and damaged cells are repaired.

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4
Q

How is cell division responsible for reproduction?

A

Unicellular organisms divide to form two identical cells that share the same structures and functions as the “parent cell”.

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5
Q

What are eukaryotic cells?

A

Cells that have a nucleus surrounded by a membrane. Plants, animals, fungi, and protists have eukaryotic cells.

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6
Q

What is the nuclear membrane?

A

It surrounds the nucleus and lets certain materials pass in and out of the nucleus.

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7
Q

What are chromosomes?

A

They direct all cell activities, and are made of DNA and protein. They are found in the nucleus. There are 23 pairs (46) of chromosomes in all human cells.

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8
Q

What are prokaryotic cells?

A

Cells with no nucleus. Bacteria have prokaryotic cells.

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9
Q

What is the nucleus?

A

It acts as the control centre of the cell, gives instructions throughout the cell by sending out chemicals (hormones), and directs all cell activities.

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10
Q

What is DNA (deoxyribonucleic acid)?

A

A molecule that is in charge of giving directions for all cell structures and activities, including repairing and replacing cells. It resembles like a long twisted ladder (Double Helix).

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11
Q

What is the nucleolus?

A

Where the ribosomes are produced and assembled. After they are made, the ribosomes move out through the nuclear membrane. The nucleolus is located in the nucleus.

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12
Q

What are ribosomes?

A

Tiny organelles that make proteins to help cells function properly. They are either free in the cytoplasm or attached to endoplasmic reticulum.

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13
Q

What is the cytoplasm?

A

It contains all the organelles in the cell. Most of the cell activities occur in the Cytoplasm. It is where nutrients are absorbed, transported and processed.

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14
Q

What is ER (endoplasmic reticulum)?

A

A series of tubes and flattened sacs that transports materials throughout the cell. Rough ER has ribosomes attached and it transports proteins. Smooth ER has no ribosomes attached and it manufactures and transports fats.

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15
Q

What are centrioles?

A

They are made of special microtubules and are found in almost all animal cells. They are active during cell division.

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15
Q

What is the Golgi apparatus?

A

An organelle that resembles a stack of pancakes. It stores proteins and puts them into vesicles, which are released outside the cell. It also makes lysosomes.

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16
Q

What are microtubules?

A

Tiny tubes found in the cytoplasm. They allow movement of the organelles within the cell and provide support for the cell.

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16
Q

What are mitochondria?

A

The power plants of cells. They give the cell energy through a process called cellular respiration.

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16
Q

What are lysosomes?

A

The “suicide sacs” of cells. They patrol and clean the cytoplasm, and break down large molecules into tinier ones so they can be recycled. They kill harmful bacteria and substances.

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17
Q

What is a vacuole?

A

An organelle that stores water, waste, and nutrients (ex. sugar). Vacuoles also get rid of waste and excess water.

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17
Q

What are chloroplasts?

A

The food factories of plant cells. They make food using chlorophyll, sun, carbon dioxide, and water.

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18
Q

What is different between plant and animal cells?

A

Plant cells have cell walls and chloroplasts while animal cells do not. Animal cells have centrioles. Plant cells also have larger vacuoles.

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19
Q

What is the structure of DNA?

A

It resembles a twisted ladder and is made of two strands of smaller molecules named nucleotides.

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21
Q

What are nucleotides?

A

They make up the sides of DNA, and are composed of a sugar molecule, a phosphate molecule, and a nitrogenous base molecule.

23
Q

How does DNA divide?

A
  1. The DNA molecule copies itself
  2. It splits down the middle (like a zipper unzipping) between the nitrogenous base pairs
  3. The old bases join up with the new bases.
25
Q

How is the genetic code created?

A

The bases of the DNA strand form “three-letter words” from three bases. (Ex. GGC or TAC). The arrangement of the letters code for the creation of over 20 amino acids. The words also form instructions for body cells to follow.

26
Q

What are nitrogenous bases?

A

The rungs of DNA. There are four different bases— adenine (A), thymine (T), cytosine (C), and guanine (G). Each base pairs up with another to form a base pair. It is always adenine+thymine and cytosine+guanine.

27
Q

What are amino acids?

A

Small molecules that are the building blocks of proteins. Specific amino acids produce different proteins. Amino acids are either manufactured by your body or are obtained from food.

28
Q

What is a genome?

A

All of an organism’s genes.

29
Q

What is protein synthesis? How does it happen?

A

The production of a protein.

  1. DNA separates (in a process similar to the duplication of a DNA strand) to make a RNA molecule.
  2. The RNA molecule carries the code from the gene to a ribosome in the cytoplasm.
  3. The ribosome “reads” the instructions on the RNA and assembles an amino acid to make a protein.
30
Q

What is a gene?

A

A short section of DNA that contains instructions to make a special protein. The instructions are determined by the order of bases. Genes are responsible for all the characteristics that make up a species.

31
Q

What are some examples of proteins?

A

Hemoglobin: carries oxygen in red blood cells
Insulin: controls the level of sugar in the blood
Keratin: makes up hair and nails
Collagen: holds tissue together, makes up bones
Enzymes: control chemical reactions
Antibodies: protects body against foreign substances
Fibrinogen: helps blood clot
Lactase: helps body digest lactose
Growth Hormone: stimulates growth
Prolactin: stimulates production and release of milk from mammary glands
Follicle Stimulating Hormone: stimulates egg and sperm production

32
Q

What is RNA (ribonucleic acid)?

A

A molecule with a structure very similar to DNA, except it only has one strand. It is in charge of carrying codes out of the nucleus to a ribosome.

33
Q

How is variety created within species?

A

There are different versions of the same gene, which results in slightly different traits, for each characteristic.

34
Q

What is the cell cycle?

A

The sequence of events in a cell from one cell division to another. There are four steps: phase of rapid cell growth, duplication of chromosomes, growth and preparation for cell division, and cell division.

35
Q

What is interphase?

A

The growing and working phase of a cell. Organelles and chromosomes in cells are duplicated at this time. A cell is in interphase for 90% of the cell cycle.

36
Q

What are the two steps of cell division?

A

Mitosis and cytokinesis.

37
Q

What is mitosis?

A

The first phase of cell division in which nuclear material is divided during cell division. Mitosis consists of four other stages: prophase, metaphase, anaphase, and telophase.

38
Q

What is cytokinesis?

A

The second phase of cell division in which the cytoplasm and organelles are divided into halves, and then distributed to two daughter cells.
In animal cells, cytokinesis can be detected by the pinching of the cell membrane and cytoplasm between the two nuclei.
In plant cells, there is no indentation. Instead, membrane-bound vesicles form between the nuclei. The vesicles fuse and form the cell plate, which continues to grow and soon becomes a new cell membrane and cell wall.

39
Q

What is prophase (mitosis)?

A

The first phase of mitosis. The sister chromatids, formed during interphase, shorten and thicken. They join at the center like an X. Meanwhile, the nucleolus is no longer visible, the nuclear membrane breaks down, and the chromosomes spread in the cytoplasm. The centrioles move to the opposite ends of the cell and start to form spindle fibres (microtubules).

40
Q

What is metaphase (mitosis)?

A

It is the second stage of mitosis. The spindle is completely formed and the sister chromatids attach to the spindle fibres. They line up along the middle of the cell.

41
Q

What is anaphase (mitosis)?

A

The third stage of mitosis. At this point, the sister chromatids are pulled apart by the spindle and move toward opposite poles of the cell. The chromatids become chromosomes again.

42
Q

What is telophase (mitosis)?

A

The fourth and final stage of mitosis. The events of prophase happen in reverse; two nuclear membranes form, the spindle disappears, the chromosomes lengthen and get thinner, and the nucleoli reappear. The original nucleus has been divided in two genetically identical nuclei.

43
Q

What is a mutation?

A

A change in the DNA or genetic code of a cell. The RNA gives altered instructions, and the amino acids, which are in the wrong order, code for proteins that aren’t the right shape and don’t function properly.

44
Q

What are some examples of mutations?

A
  • Green Eyes: They are a mutation of blue eyes.
  • Cystic Fibrosis: A protein that helps move certain chemicals in and out of a cell doesn’t function due to shape change. People with cystic fibrosis have buildup of thick mucus in their lungs.
  • Diabetes: Insulin, a protein that controls the amount of sugar in blood, either doesn’t work or isn’t produced.
45
Q

What is cancer?

A

A disease in which cells divide rapidly and uncontrollably. There is a mutation in the genes that control cell division. When cancer cells divide, they create daughter cells with the same mutation.

46
Q

What is a tumour?

A

A mass of cells that accumulates when they keep dividing.

47
Q

What is a benign tumour?

A

A tumour that grows but stays in one place. It does not interfere with normal functioning of surrounding tissues or organs. Benign tumours can usually be removed by surgery. (Ex. a wart).

48
Q

What is a malignant tumour?

A

A tumour that invades surrounding tissues and organs and interferes with the body’s functions.

49
Q

What are the unique characteristics of cancer cells?

A

They have highly visible enlarged nuclei and continue to divide even if they are separated from neighboring cells. They can separate and spread to other parts of the body.

50
Q

What is metastasis?

A

The spread of cancer cells away from their original location.

51
Q

What is a carcinogen?

A

Any substance that causes Cancer. (Ex. tobacco, pesticides, X-rays, asbestos).

52
Q

What are the types of asexual reproduction?

A

Binary fission, budding, vegetative reproduction, fragmentation and spore formation.

53
Q

What is sexual reproduction?

A

When two separate organisms contribute genetic information, in specialized sex cells (an egg and sperm cell) to produce a zygote, the first cell of a new organism.

54
Q

What is asexual reproduction?

A

It involves only one parent. All offspring are clones. They are identical to the parent and share the same DNA. A single parent can produce large numbers of offspring from asexual reproduction.

55
Q

What is binary fission?

A

The type of reproduction unicellular organisms use. The parent undergoes cell division to produce two identical daughter cells. The offspring are smaller than the parent cell, but they have all the necessary structures. Binary fission allows rapid population growth, but there is no variety and no different immunities within a species.

56
Q

What is budding?

A

It starts with the offspring as a small bud on the parent. It undergoes cell division and grows in size before breaking off from the parent. Budding happens in both unicellular (yeast) and multi-cellular (hydra) organisms.

57
Q

What is vegetative reproduction?

A

In which plants reproduce asexually. Some plants like strawberries send out runners, a type of stem that grows it’s own roots and can become an individual plant, while some trees and shrubs send out shoots and cuttings, which also can grow into new plants. Bulbs and tubers are other forms of vegetative reproduction.

58
Q

What is spore formation?

A

When spores, cells with thick cell walls, are formed by fungi, algae, and non-flowering plants. These spores are similar to seeds except they are produced by cell division. Organisms that form spores may also reproduce sexually.

Science 9 (8 decks)

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