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Cells Flashcards

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1
Q

Living organisms are classified into 3 domains:

A

Bacteria, Archaea and Eukarya

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2
Q

Which domain(s) are pokaryotic?

A

Bacteria and archaea

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2
Q

Which domain(s) are eukaryotic?

A

Eukarya

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3
Q

Characteristics of prokaryotes

(4)

A
  • single celled organisms
  • Lack membrane-bound organelles
  • DNA is not seperated from the cytoplasm in a nucleus
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3
Q

What can be said about bacteria

(2)

A

Bacteria are the most diverse and widespread prokaryotes and are now classified into multiple kingdoms.

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3
Q

What can be said about archaea?

A

Archaea live in Earth’s extreme environments, such as salty lakes and boiling hot springs.

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4
Q

Characteristics of eukarotes

(3)

A
  • contain membrane bound organells
  • more complex organisms
  • DNA in a nucleus - seperated from the cytoplasm by a membrane
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4
Q

Domains of eukarya

(4)

A
  1. Plantae
  2. Fungi
  3. Animalia
  4. Protista
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5
Q

3 major characteristics of prokaryotic cells

(3)

A
  1. Within the cytoplasm, much less and/or smaller organelles or none
  2. Rigid cell walls: surrounding the plasma membrane
  3. No membrane bound nucleus: the genetic material (DNA) is found in the nucleoid region
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6
Q

Cytoplasm

A

the region between the nucleus and the membrane bounding the cell which consists of a semifluid medium called the cytosol, in which are found various organelles.

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7
Q

What can be said conserning the size of eukaryotic and prokaryotic cells?

A

Eukaryotic cells are generally much larger than prokaryotic cells

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8
Q

Why are cells small

A

a smaller object has a greater ratio of surface area to volume

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9
Q

Do larger organisms have larger cells than smaller organisms? Explain

A

No, they do not. They simply have more cells

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10
Q

Example of a cell where a high ratio of surface area to volume is important

A

Intestinal cells

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11
Q

What is one way to increase surface area without a big increase in volume?

A

Microvilla - long projections on cells surfaces

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12
Q

Key roles of the cell membrane

(5)

A
  1. Controlling cell function
  2. cell adhesion
  3. recognition and communication
  4. keeping its molecules of life from dissipating away
  5. keep out foreign molecules that damage or destroy the cells components and molecules
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13
Q

The plasma membrane and the various internal membranes of cells consist of a _______ of ________ with _____________ attached to or imbedded in it.

A

The plasma membrane and the various internal membranes of cells consist of a double layer of phospholipids with proteins attached to or imbedded in it

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14
Q

What is found along the membrane apart from phospholipids?

A

Proteins

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15
Q

Nucleus

A

Contains DNA and controls cellular activity

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16
Q

Nucleolus

A

A region where components of ribosomes are synthesized and assembled

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17
Q

What happens after ribosomes are asesembled in the nucleolus?

A

They pass through the nuclear pores to the cytoplasm, where they combine to form ribosomes (the site of protein synthesis)

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18
Q

the DNA is organized along with proteins into a material called _______

A

the DNA is organized along with proteins into a material called chromatin

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19
Q

What happens to chromatin as a cell prepares to divide?

A

the stringy, entangled chromatin coils up (condenses) becoming thick enough to be discerned as separate structures called chromosomes

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20
Q

What is a chromosome formed from?

A

A chromosome is formed from a single DNA molecule that contains many genes

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21
Which organelles are apart of the endomembrane system? (7)
the nuclear membrane, the endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, endosomes, and plasma membrane
22
Who am I? So thin cannot be resolved under a light microscope
Endomembrane system
23
Function of the endomembrane system
- fills the cell + divides it into compartments - provides surfaces for protein and lipid synthesis
24
Endoplasmic reticulum (ER)
largest of the internal membranes composed of a lipid bilayer
25
Two parts of the ER
**Rough ER** -studded with ribosomes involved in protein synthesis **Smooth ER**- lacks ribosomes
26
ER membrane weaves in sheets through the interior of the cell, creating a network of membranous tubules and sacs called _______
ER membrane weaves in sheets through the interior of the cell, creating a network of membranous tubules and sacs called **cisternae**
27
Cisternae
network of membranous tubules and sacs called within the ER
28
Smooth ER | (4)
- lacks ER - Synthesizes lipids - Metabolises carbohydrates - detoxification of drugs and poisons
29
Rough ER | (3)
- contains ribosomes - Ribosomes are the site of protein synthesis - When proteins are made for export the amino acids (building blocks of proteins) are threaded through the rough ER into it’s internal space.
30
Give an example of a specialized cells that secrete proteins produced by ribosomes attached to rough ER
Cells in the pancreas secrete insulin, a hormone, into the bloodstream
31
Most secretory proteins are ________, proteins that are covalently bound to __________
Most secretory proteins are **glycoproteins**, proteins that are covalently bound to **carbohydrates**
32
How do secretory proteins leave the ER
Secretory proteins leave the ER **wrapped in the membranes of vesicles that bud like bubbles from the ER**. Such vesicles in transit from one part of the cell to another are called transport vesicles.
33
How does rough ER grow
rough ER grows in place by **adding proteins and phospholipids to itself**
34
Golgi structure and explain the process | (4)
- has a front and a back, with different membrane compositions - front end = cis face ; is located near the ER - vesicles fuse with the cis face, emptying their contents into the interior or lumen of the Golgi apparatus - ER-synthesized molecules then pass through the channels of the Golgi apparatus until they reach the back called the trans face, where they are discharged in secretory vesicles
35
Golgi apparatus
- functions in the **coll****ection, packaging and distribution of molecules** synthesized in one place in the cell and used at another - Golgi **modifies and sorts proteins prior to export**
36
Membrane bound organelles | (11)
Plasma membrane, cytoplasm, nucleus, ER, Golgi, vesicles, lysosomes, peroxisome, mitochondria, chloroplasts, vacuoles
37
Non membrane bound organelles | (8)
Nucleolus, ribosomes, cytoskeleton, centrosome, cilia, flagella, cell wall, extracellular matrix
38
Lysosomes
membrane-bound sac of hydrolytic enzymes that an animal cell uses to digest macromolecules
39
What cen lysosomes hydrolyze?
nucleotides, proteins, lipids, phospholipids--all the major classes of macromolecules
40
How do lysosomes arise
The lysosomes arise **from budding from the trans face of the Golgi apparatus**
41
Peroxisome
- The peroxisome is a specialized metabolic compartment bounded by a single membrane - Contain enzymes that remove H atoms from various substrates and transfer them to O2
42
Peroxisome function
break fatty acids down into smaller molecules that are transported to mitochondria and used as fuel
43
Peroxisomes in the liver
peroxisomes in the liver **detoxify alcohol and other harmful compounds by transferring hydrogen from the poisons to O2**
44
Mitochondria
Mitochondria are the cells' power sources and are found in nearly all eukaryotic cells **Cellular respiration: Chemical energy in food (ex glucose) converted → ATP**
45
Chloroplast
- Phosynthesis - production of glucose - Contains a green pigment - chlorophyll
46
# Chloroplast they grow and occasionally ____________ reproducing themselves
they grow and occasionally **pinch in two,** reproducing themselves
47
Like mitochondria chloroplast are surrounded by a __________
Like mitochondria chloroplast are surrounded by a **double membrane**
48
Origin of Mitochondria and Chloroplasts, name
Serial Endosymbiosis
49
Serial Endosymbiosis
mitochondria and chloroplasts, **originated from the engulfing, incorporation and then coevolution of smaller prokaryotic organisms into the larger eukaryotic cell**
50
Symbiosis
Two different species living in direct contact with each other. In this case, the two partners became mutually beneficial.
51
Endosymbiosis
Symbiotic relationship in which the smaller species live inside the larger species
52
Vacuoles (what and function)
- large vesicles derived from ER and Golgi apparatus - perform a variety of functions in different cells
53
In plants, smaller vacuoles can hold reserves _____________ such as the proteins stockpiled in the storage cells in seeds
In plants, smaller vacuoles can hold reserves **of important organic compounds,** such as the proteins stockpiled in the storage cells in seeds
54
Vacuoles may also help protect the plant against herbivores by ___________
Vacuoles may also help protect the plant against herbivores by **storing compounds that are poisonous or unpalatable to animals**
55
Some plant vacuoles contain _____
Some plant vacuoles contain **pigments**
56
Central Vacuole | (2)
- The main function: to **maintain turgor pressure in the cell** - Turgor pressure is the pressure of the cell’s contents pushing against the cell wall; it is only found in cells that have cell walls, such as those of plants, fungi, and bacteria
57
Central vacules - how they come to be and what it contains
- Mature plant cells generally contain a large central vacuole which develops by the merging of smaller vacuoles - The solution inside the central vacuole, called cell sap, is the plant cell’s main store of inorganic ions
58
The central vacuole can be up to what percentage of the plant cell volume
The central vacuole can be up to 90% of the plant cell volume.
59
What happends if the vacuole is not filled
If the vacuole is not filled **the plants wilt**
60
Where are ribosomes found
ribosomes are found free in the cytosol
61
Cytoskeleton - what is it
network of fibers extending throughout the cytoplasm
61
62
The three molecular structures of the cytoskeleton
1. microtubules 2. microfilaments 3. intermediate filaments
63
Cytoskeleton - function | (2)
- To give mechanical support to the cell - To maintain its shape (especially important for animal cells, which lack walls)
64
Microtubules | (4)
- thickest of the 3 types of fibers - hollow rods of protein called **tubulin** which is a dimer, a molecule made up of two subunits - Microtubules **shape and support the cell** and also **serve as tracks along which organelles equipped with motor proteins can move**
65
# Who am I - involved in the separation of chromosomes during cell division - Found in flagella and cilia
Microtubules
66
Centrosome
- microtubules grow out from a centrosome
67
Where are centrosomes located
located near the nucleus
68
# Who am I? considered a “microtubule-organizing center"
Centrosome
69
Where are centrioles found
a pair of centrioles is found **within the centrosome**
70
What is responsible for the beating of flagella and cilia
specialized arrangement of microtubules
71
Flagella characteristics
longer and there is usually only one per cell
72
Motile cilia usually occur in ______ numbers on the cell surface
Motile cilia usually occur in **large** numbers on the cell surface.
73
Flagella and cilia beating patterns
- Flagella: undulating motion that generates force in the same direction as the flagellum’s axis - Cillia: alternating power and recovery strokes generating force in a direction perpendicular to the cilium’s axis
74
Found in plant cells not in animal cells | (3)
- Cell wall - Central vacoule - Chloroplast
75
Found in animal cells not plant cells | (2)
- Centrosome - Lysosome
76
Cell Wall of Plants - functions | (4)
- Protects the cell - Maintains its shape - Prevents excessive uptake of water - Hold the plant up against the force of gravity
77
Whats thicker? Plant cell walls or plasma membrane?
Plant cell walls
78
What are plant cell walls made up of?
the polysaccharide cellulose
79
What are membrane proteins attacted to
The **cytoskeleton**
80
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