Cell Biology Flashcards

1
Q

What do microscopes do?

A

Magnify the image of a biological specimen so that it appears larger.

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2
Q

Name the 9 parts of a microscope

A

Eyepiece, coarse focus, fine focus, objective lenses, stage clip, condenser, arm, stage, mirror

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3
Q

What is the formula to calculate magnification?

A

Magnification=size of image(image size)/real size of image(actual size)

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4
Q

The ability to see greater detail in an image depends on the r…?

A

Resolution or resolving power

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5
Q

What does the electron microscope use instead of light rays?

A

Electron microscopes use a beam of electrons instead of light rays.

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6
Q

What are the two types of electron microscopes?

A

The scanning electron microscope (SEM) and the transmission electron microscope (TEM).

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7
Q

What does the scanning electron microscope examine?

A

The SEM has a large field view so can be used to examine the surface structure of specimens. SEMS are often used at lower magnifications.

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8
Q

What does the transmission electron microscope examine?

A

The TEM is used to examine thin slices or sections of cells or tissues.

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9
Q

What is the function of the nucleus?

A

Contains generic material, including DNA, which controls the cell’s activities.

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10
Q

What is the function of cytoplasm?

A

A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It is where many of the chemical reactions happen.

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11
Q

What is the function of cell membrane?

A

It’s structure is permeable to some substances but not to others. It therefore controls the movement of substances in and out of the cell.

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12
Q

What is the function of mitochondria?

A

Organelles that contain the enzymes for respiration, and where most energy is released in respiration.

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13
Q

What is the function of ribosomes?

A

Tiny structures where protein synthesis occurs.

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14
Q

What the difference between plant and animal cells?

A

Plant cells have a permanent vacuole and a cell wall and chloroplasts, animal cells don’t.

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15
Q

What is the function chloroplasts?

A

Organelles that contains the green pigment, chlorophyll, which absorbs light energy for photosynthesis. Contains the enzymes needed for photosynthesis.

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16
Q

What is the function of the cell wall?

A

Made from cellulose fibres and strengthens the cell and supports the plant.

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17
Q

What is the function of a permanent vacuole?

A

Filled with cell sap to help keep the cell turgid.

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18
Q

What cells are prokaryotic cells?

A

Cells of bacteria are called prokaryotic cells.

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19
Q

What are cells of eukaryotic cells?

A

Cells of animals, plants and fungi are called eukaryotic cells.

20
Q

What type of cell division do eukaryotic cells use?

A

Mitosis

21
Q

What type of cell division do prokaryotic cells use?

A

Binary fission

22
Q

How is a sperm cell specialised for its role?

A

The head of the sperm contains the genetic material for fertilisation. The acrosome in the head contains enzymes so that the sperm can penetrate an egg. The middle piece is packed with mitrochondria to release energy needed to swim and fertilise the egg. The tail enables the sperm to swim.

23
Q

How is the nerve cell specialised for its role?

A

The nerve cell is extended, so that the nerves can run to and from different parts of the body to the central nervous system. The cell has extensions and branches, so that it can communicate with other nerve cells, muscles and glands. The nerve cell is covered with a fatty sheath, which insulates the nerve cell and speeds up the nerve impulse.

24
Q

How are muscle cells specialised for their role?

A

Muscle cells contain filaments of protein that slides over each other to cause muscle contraction. The arrangement of these filaments causes the banded appearance of heart muscle and skeletal muscle. They contain many well-developed mitochondria to provide the energy for muscle contraction. In skeletal muscle, the cells merge so that the muscle fibres contract in unison.

25
Q

How is a root hair cell specialised for its role?

A

The root hair cell has a large surface area to provide contact with soil water. It has thin walls so as not to restrict the movement of water.

26
Q

How is a xylem cell specialised for its role?

A

There are no top and bottom walls between xylem vessels, so there is a continuous column of water running through them. Their walls become thickened and woody (thickened with lignin). They therefore support the plant.

27
Q

How is a phloem cell specialised for its role?

A

Dissolved sugars and amino acids can be transported both up and down the stem. Companion cells, adjacent to the sieve tubes provide energy required to transport substances in the phloem.

28
Q

In females, the two chromosomes are identical in shape. What are the Females chromosomes referred to as?

A

XX

29
Q

In males, one of the chromosomes is a different in shape. What are the male chromosomes referred to as?

A

XY

30
Q

When do cells divide?

A

Cells divide when an organism grows or an organism becomes damaged and needs to produce new cells.

31
Q

What happens in mitosis?

A

In mitosis , two cells called daughter cells are produced, each identical to the parent cell.

32
Q

What happens during the stages of mitosis?

A

The cell begins to divide
The DNA replicates to form two copies of each chromosome
The nuclear membrane breaks down. The chromosomes line up across the centre of the cell
One set of chromosomes is pulled to each end of the cell and the nucleus divides
The cytoplasm and cell membranes divide to from two identical cells

33
Q

When looking at cells with a microscope, the length of different stages of the cell cycle can be estimated using what formula?

A

Length of time in phase=observed number of cells at that stage/total number of cells observed X total length of time of cell cycle

34
Q

What are stem cells?

A

Stem cells are cells that have not undergone differentiation. A cell which has not yet become specialised is called undifferentiated.

35
Q

What are embryonic stem cells?

A

Cells at the early stages of an embryo are stem cells. If cells are removed from the embryo they will differentiate into any cell type.

36
Q

What are adult stem cells?

A

Adult stem cells can be found in the: brain, eyes, blood, heart, liver, bone marrow, skin and muscle. Adult stem cells can differentiate into related cell types only.
E.g. bone marrow cells can differentiate into blood cells and cells of the immune system but not other cells types.

37
Q

What is a meristem?

A

Cell division in plants occurs in regions called meristems. Cells of the meristem can differentiate to produce all types of plant cells at any time during the life of the plant.

38
Q

Where can meristems be found?

A

The main meristems are close to the tip of the shoot, and the tip of the root.

39
Q

(Specialised cells in animals) What are cells of the circulatory system specialised to do?

A

Specialised to transport substances, defend the body, regulate temperature.

40
Q

(Specialised cells in animals) What are cells of the excretory system specialised to do?

A

Specialised to remove waste product and unwanted substances, regulate the water content of the body.

41
Q

(Specialised cells in animals) What are cells of the muscular system specialised to do?

A

Specialised to bring about movement.

42
Q

(Specialised cells in animals) What are cells of the nervous system specialised to do?

A

Specialised to internal and external stimuli and conditions, carry messages for the body work as a coordinated whole.

43
Q

(Specialised cells in animals) What are cells of the respiratory system specialised to do?

A

Specialised to deliver oxygen for respiration and remove waste.

44
Q

(Specialised cells in animals) What are cells of the reproductive system specialised to do?

A

Specialised to bring about fertilisation to produce new offspring.

45
Q

(Specialised cells in animals) What are cells of the skeletal system specialised to do?

A

Specialised to bring about movement, support and protect internal structures, produce blood cells, store and release calcium.

46
Q

(Specialised cells in plants) What are cells of the (leaf) palisade mesophyll specialised to do?

A

Specialised to carry out photosynthesis.