Chapter 1 - Cells Flashcards

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0
Q

How are cells divided?

A

Prokaryotic and eukaryotic (plants and animal)

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1
Q

What is a cell?

A

A small, membrane bound compartment that contains all the chemicals & molecules that help support an organisms life.

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2
Q

What is a prokaryotic?

A

It’s an unicellular, that lacks membrane bound organelles.

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3
Q

What is an organelle?

A

An organised structure that is found in cells, it’s distinctive in shape and function.

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4
Q

Name 3 similarities between a plant cell and an animal cell.

A

Nucleus, mitochondria, Golgi apparatus, endoplasmic reticulum and lysosomes.

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5
Q

Name 3 differences between plant cells and animal cells.

A

Cell wall, large vacuoles, and chloroplasts

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6
Q

What is a capsule?

A

A thick polysaccharide layer outside of the cell wall. It’s used for sticking cells together, food reserve and protection.

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7
Q

In prokaryotes, what is a cell wall?

A

It’s made of murein, which is a glycoprotein.

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8
Q

What is a flagellum?

A

It’s a rigid rotating helical shaped tail used for propulsion. Either uses clockwise rotation to move forwards or anticlockwise rotation to give it a chaotic spin.

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9
Q

What is the cell membrane?

A

It’s a thin, flexible layer made of phospholipids and proteins

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10
Q

What are plasmids?

A

Small circles of DNA, used to exchange between bacterial cells

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11
Q

What is a nucleotide?

A

Region of the cytoplasm that contains DNA, does not have a nuclear membrane.

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12
Q

What is DNA?

A

Always circular and not associated with any proteins to form chromatin

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13
Q

What is cytoplasm in prokaryotes?’

A

Contains all the enzymes needed for metabolic reactions since there are no organelles

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14
Q

What is a mesosome?

A

Tightly folded region of the cell membrane containing all the membrane bound proteins required for respiration and photosynthesis.

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15
Q

What is cytoplasm in a eukaryote?

A

Aqueous substance within cell membrane containing organelles, sugars, salts and amino acids. Vital metabolic reactions happen here.

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16
Q

What is a nucleus?

A

It controls the activities of the cell, containing DNA which regulated chemical reaction. Largest organelle and spherical in shape. Has 2 membranes.

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17
Q

What 2 things are found in a nucleus?

A

Chromatin which is composed of coils of DNA wrapped around histones which form nucleosomes. Nucleolus are rounded darkly stained structures which manufactures RNA.

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18
Q

What is the plasma membrane?

A

It separates the contents of the cell from outside environment, and controls what enters and exits.

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19
Q

What is a mitochondria?

A

It’s the powerhouse of all eukaryotic aerobic cells. Carries out aerobic respiration and gives energy to cell.
Also site of ATP synthesis.

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20
Q

What’s special about the mitochondria?

A

It has 2 membrane envelopes. The outer which is simple and permeable. The inter with is highly folded with cristae, giving it a large surface area. Space enclosed is referred to as the Matrix.

21
Q

What are ribosomes?

A

Smaller and most numerous organelles. Site of protein synthesis. Manufactured in the nucleus. It is composed of 2 subunits: protein and ribosomal RNA.

22
Q

Where can you find ribosomes?

A

Either found free in the cytoplasm, making proteins for the cell or attached to the rough ER, making proteins for export from the cell.

23
Q

There are 2 sizes of ribosomes, where are they found?

A

The smaller ribosome’s are found in prokaryotes, whereas the larger ones are found in eukaryotes.

24
Q

What is the endoplasmic reticulum?

A

Consists of flattened cavities called cisternae, made up of parallel membranes.

25
Q

There are 2 types of endoplasmic reticulum. State them.

A

Smooth ER: a series of membrane channels involved in synthesising and transporting materials (mainly lipids and steroids)
Rough ER: similar to the smooth but studded with ribosomes, which synthesise protein before being exported by the Golgi Body.

26
Q

What is the Golgi Body/Apparatus?

A

Consists of a stack of flattened, membrane coins sacs called cristernae and Golgi vesicles.
Transport & chemically modify the material containing it and form lysosomes.

27
Q

What is a vacuole?

A

Membrane bound sacs containing water and dilute solutions of salts. Plants unlike animals have large permanent ones filled with cell sap. Important for keeping cell rigid or turgid.

28
Q

What are lysosomes?

A

Small bound vesicles, from the rough ER, containing digestive enzymes.
Used to break down unwanted toxins, chemicals and organelles.

29
Q

What is a cytoskeleton?

A

Network of protein fibres extending throughout all eukaryotes. Used for support and transport.
Gives shape as well as holds all organisms together.

30
Q

There are 3 types of protein fibres, name them.

A

Microfillament, intermediate filament and microtubes.

31
Q

What are centrioles?

A

Pair of short microtubes involved in cell division.
Before each division the centriole replicates itself and moves to opposite ends of the cell, where they initiate the spindles.

32
Q

What is an undulipodium?

A

Long flexible tail present in some cells, used for motility.
Extension of cytoplasm and full of microtubes & motor proteins.

33
Q

There are 2 kinds of undulipodium, state them.

A

Flagellum (eukaryotic one) longer than cell and usually one or two of them present.
Cilia: are identical in shape but much smaller and are much more numerous.

34
Q

What are micro villi?

A

Small finger like extensions of the cell membrane. Increases surface area.

35
Q

What are chloroplasts?

A

Contains green pigment called chlorophyll, giving plants their colour.
Where photosynthesis takes place.
Site of ATP synthesis too.

36
Q

What’s special about chloroplasts?

A

Like the mitochondria it’s enclosed in a double membrane.
Thylakoids disks which are stacked into piles called grana
Space between inner membrane and thylakoids is stroma.

37
Q

What is a cell wall in eukaryotes?

A

It’s a fully permeable, non living structure that helps the cell kept its shape. Made of cellulose unlike prokaryotes.
Primary wall formed in cell division of plants. Secondary wall formed later with more lignin.

38
Q

What is lignin?

A

Cements and anchors cellulose fibers together.
Protects from physical/chemical damage.
Causes cells to die (xylem)

39
Q

Functions of the cell wall?

A

Semi-rigid structure provides shape and support.
Resistant to expansion and allows of turgidity when water enters.
Walls are held together by middle lamellae which posses minute pores called plasmodesmata.
It develops a waxy cuticle to lessen water loss.

40
Q

What are plasmodesmata?

A

Living connections between neighbouring plant cells through fine pores.
Communication & coordinating made easier.

41
Q

What are some characteristics of unicellular organisms?

A

Surface area to volume increases in order for much of the cytoplasm to come in contact with outside.
Gases & wastes can be exchanged directly to outside through surface.

42
Q

What are some of the characteristics of multicellular organisms?

A

Smaller surface area to volume ratio. Some cells don’t come in contact with outside environment.

Develop specialised organs & systems to carry out particular functions.

43
Q

What is the endosymbiosis theory?

A

Tried to explain how eukaryote cells arose since prokaryotes are older and simpler.
Therefore eukaryotes had to evolve from them.

44
Q

What is endosymbiosis?

A

‘Living within’ another cell or organism. Creation of double membrane.
Mitochondria and chloroplasts could have originally been a cell which engulfed another.

45
Q

Similarities which favour endosymbiosis.

A

Functions of bacterial plasma membrane and mitochondria inner membrane.
Primary structure of certain bacteria and mitochondrial enzymes.

46
Q

In relevance to light microscopes, what is a glass slide used for?

A

It’s used to out specimens on it, which is then covered by a cover slip.

47
Q

What is an iris diaphragm?

A

It’s used for controlling light intensity on the light microscopes.

48
Q

What is an electron microscope?

A

It uses a beam of electrons rather than electromagnetic radiation.
2000x & possible to view 3 dimensional shapes.

49
Q

In relevance to electron microscopes, what is staining used for?

A

Most biological structures are transparent, so some contrast is needed in order to differentiate between structures.

50
Q

Mention some stains and what the colour indicates.

A

Eosin goes Pink/Red when cytoplasm of cellulose is present.
Methylene blue turns blue when nucleus is present.
Iodine solution turns blue/black when starch is present.