Unit1 Module 1 Cells Flashcards

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0
Q

What is resoloution?

A

The extent to which one can distinguish between 2 objects very close together. The higher the resoloution, the more detail you can see.

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1
Q

What is magnification?

A

How many times the image is larger than itself

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2
Q

Function/structure of nucleus

A

Where the genetic material is stored (DNA)

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3
Q

Function/structure of nucleolus?

A

Dense centre of nucleolus. Makes RNA and ribosomes.

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4
Q

Function/structure of nuclear envelope??

A

Surrounds nucleus with double membrane. The multiple pores regulate passage of macromolecules but allows free access to smaller molecules.

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5
Q

Function/structure of SER?

A

Involved in the synthesis of lipids

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6
Q

Function/structure of RER?

A

Transport and synthesis of proteins

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7
Q

Function/structure of Golgi apparatus?

A

Modifies proteins from the RER and then packages them into vesicles that can be transported

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8
Q

Function/structure of ribosomes?

A

Site of protein synthesis

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9
Q

Function/structure of mitochondria?

A
Double membrane (highly folded inside) 
Where ATP is produced
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10
Q

Lysosomes

A

Contains powerful digestive enzymes that break down materials

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11
Q

Chloroplasts

A

Site of photosynthesis in plant cells

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12
Q

Function/structure of centrioles

A

Microtubules of protein fibres

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13
Q

Describe the production and synthesis of proteins. 6 steps.

A

MRNA gene for protein is made in the nucleus. It leaves the nucleus and attaches to a ribosome on RER. The ribosome assembles the protein. Proteins are pinched off in vesicles and go to the Golgi apparatus. The Golgi apparatus packages protein ready for release. It is secreted at the cell surface membrane.

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14
Q

Prokaryotic cells vs eukaryotic cells (4 things)

A
  • Prokaryotic is much smaller than eukaryotic
  • prokaryotic only has one membrane (at the cell surface) and no membrane bound organelles
  • even the DNA is not surrounded by a membrane, unlike the nuclear envelope of eukaryotic cells
  • cell wall is made of Murien, not cellulose
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15
Q

Four roles of membranes?

A

Separating cell contents from the outside environment
Separating cell components from the cytoplasm
Cell signalling
Regulating the transport of materials in and out of the cell

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16
Q

What two words best describe plasma membranes?

A

Partially permeable

17
Q

The role of phospholipids? (2 things)

A

The hydrophobic layer formed by the phospholipid tails creates a basic barrier and separates the cell contents from the outside world

18
Q

Role of cholesterol in fluid mosaic model?

A

Gives the membrane stability as it fits between the fatty acid tails

19
Q

Role of glycolipds/glycoproteins in the fluid mosaic model??

A

Involved in cell signalling

20
Q

What are the two different proteins in the fluid mosaic model and what are their roles?

A

Channel proteins - helps the movement of large, hydrophilic substances across the membrane
Carrier proteins - actively moves substances across the membrane

21
Q

How do hormone receptors work?

A

A hormone molecule binds to a receptor on a target cell because the two have complimentary shapes. This causes the target cell to respond in a certain way.

22
Q

What is diffusion?

A

The net movement of molecules from an area of high conc to a region of low conc down the concentration gradient

23
Q

Effect of temperature on fluid mosaic?

A

Increase in temp gives molecules more kinetic energy so they move faster. The increased movement of phospholipids etc makes the membrane leaky allowing substances that normally wouldn’t to enter/leave the cell.

24
Q

What is cell signalling?

A

Cells communicate with each other by signals

25
Q

Four factors that effect patted rate of diffusion

A

Temperature - more kinetic energy, so the movement of molecules increases and the ROD increases.
Concentration gradient - having more molecules on one wide increases the concentration gradient and the ROD
Surface area - ROD increases if there is a greater surface area to diffuse across
Distance/thickness - diffusion is slowed down by thick membranes

26
Q

What is active transport?

A

The movement of molecules across the concentration gradient, requiring ATP

27
Q

How is active transport different from facilitated diffusion?

A

They use energy in the form of ATP and it is much faster than diffusion.

28
Q

What happens to the carrier protein during active transport? Why is this important?

A

The shape is changed so the molecule it carries fits on one side of the membrane only.

29
Q

What is the definition of osmosis?

A

The net movement of water molecules from an area of high water potential to an area of low water potential across a partially permeable membrane.

30
Q

What happens to cells in a high water potential area?

A

The water molecules will enter the cell by osmosis. In an animal cell, the cell membrane will eventually burst open. A plant cell will remain turgid as the cell wall will prevent it from bursting.

31
Q

What happens to cells in a low water potential area?

A

The water molecules move out of the cell by osmosis. Plant cells experience plasmolysis, where the cell membrane pulls away from the cell wall. Animal cells shrink and appear wrinkled.

32
Q

What is formed by mitosis?

A

Two genetically identical nuclei

33
Q

Describe prophase (3 things)

A

Chromosomes condense
Nuclear envelope breaks down
The centrioles move to opposite ends to form the spindle

34
Q

What happens in metaphase?

A

The chromosomes line up and are attached to the spindle thread by their centromeres

35
Q

What happens in anaphase? (Two things)

A

Chromatids split so there is twice as many chromosomes

The spindle fibres shorted so the chromosomes are pulled towards opposite ends

36
Q

What happens in telophase? (3 things)

A

Nuclear envelope reforms
Chromosomes decondense
The whole cell splits to form two new cells

37
Q

Why can’t most cells undergo mitosis?

A

Because of their cell walls

38
Q

How are red blood cells (erythrocytes) differentiated? (3 things)

A

They have no nucleus, or other organelles like mitochondria. They are packed with haemoglobin and they are biconcave (to increase surface area)

39
Q

How do you calculate the linear magnification of an image?

A

Magnification = image size/actual size