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BIO 201 > Chapter 4 > Flashcards

Chapter 4 Flashcards

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Biology 101 flashcards
1
Q

Cell Theory

A

All organisms are composed of cells
All cells come only from preexisting cells
Cells are the smallest structural and functional units

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2
Q

Cell Theory

A

All organisms are composed of cells
All cells come only from preexisting cells
Cells are the smallest structural and functional units

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3
Q

Cell Size

A

Range in size from one millimeter to one micrometer
Cells need a large surface area to exchange materials

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4
Q

What is Surface-area-to-volume ratio

A

Requires that cells can be small
Large cells-surface area relative to volume decreases

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5
Q

Prokaryotic Cells

A

Lack a membrane-bound nucleus
Structurally smaller and simpler the eukaryotic cells (which have a nucleus)

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6
Q

What is The membrane-bound nucleus

A

Contains the genetic material (DNA) and directs all cell functions.

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7
Q

Are bacteria classified as prokaryotes?

A

Bacteria are classified as prokaryotes because they lack a nucleus and membrane-bound organelles.

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8
Q

What are Cell Organelles?

A

The cellular components are called cell organelles. These cell organelles include both membrane and non-membrane bound organelles, present within the cells and are distinct in their structures and functions

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9
Q

Bacteria occur in three basic shapes

A

Spherical coccus
Red Shape bacillus
Spiral spirillum (if rigid) or spirochete (if flexible)

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10
Q

Spherical Coccus

A

Cocci shaped bacteria are microorganisms with a spherical or oval shape. These bacteria can exist as single organisms or in various clusters,

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11
Q

Rod shaped Bacillus

A

Rod-shaped bacteria are termed bacilli. Most of the rod-shaped bacteria are soil microorganisms in which some are parasitic

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12
Q

Spiral spirillum

A

A bacterium with rigid spiral (helical) structure (not easily band, not flexible), thick, long, and move with flagella, 6–15 μm long and spiral in shape

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13
Q

Spiral spirochete

A

most of which have long, helically coiled (corkscrew-shaped or spiraled, hence the name) cells.

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14
Q

Bacteria Cell Envelope includes

A

Plasma membrane
Cell wall
Glycocalyx

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15
Q

Plasma Membrane

A

Lipid (compounds that are insoluble in water) bilayer with embedded and peripheral (situated on the edge) proteins

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16
Q

Cell Wall

A

Maintains the shape of the cell and is strengthened by peptidoglycan (complex polymer composed of sugars and amino acids)

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17
Q

glycocalyx

A

Layer of polysaccharides on the outside of the the cell acting as a skeleton

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18
Q

What is cytoplasm

A

Semifluid solution bounded by plasma membrane
Contains water inorganic and organic molecules and enzymes

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19
Q

Cytoplasm also has two regions

A

Nucleoid The nucleoid (meaning nucleus-like) is an irregularly shaped region within the prokaryotic cell that contains the single circular DNA
Plasmids is a small circular DNA molecule found in bacteria and some other microscopic organisms. Plasmids are physically separate from chromosomal DNA and replicate independently.

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20
Q

Cytoplasm also has two regions

A

Nucleoid The nucleoid (meaning nucleus-like) is an irregularly shaped region within the prokaryotic cell that contains the single circular DNA
Plasmids is a small circular DNA molecule found in bacteria and some other microscopic organisms. Plasmids are physically separate from chromosomal DNA and replicate independently.

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21
Q

Domain Eukaryotic cells includes

A

animals, plants, fungi, and protists or protoctists (protoctist is any eukaryotic organism that is not an animal, land plant, or fungus)

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22
Q

Are eukaryotic cells larger or smaller than prokaryotic cells

A

Much larger

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23
Q

Eukaryotic cells contain

A

Membrane-bound nucleus that houses DNA
Specialized organelles
Plasma membrane
Some cells (e.g.,plant cells) have a cell wall

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24
Q

What is endosymbiotic theory

A

Membranes — Mitochondria (membrane-bound cell organelles) have their own cell membranes just like a prokaryotic cell does.
DNA — Each mitochondrion has its own circular DNA genome, like a bacteria’s genome, but much smaller. …
Reproduction — Mitochondria multiply by pinching in half — the same process used by bacteria.

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25
Q

What are bacteria appendages

A

Flagella - provide motility (the ability of an organism to move independently, using metabolic energy)

Fimbriae – small, bristle-like fibers that sprout from the cell surface
Conjugation pili – rigid tubular structures used to pass DNA from cell to cell

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26
Q

Eukaryotic cells are compartmentalized

A

They contain small structures called organelles which Perform specific functions and Isolate certain chemical reactions from others

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27
Q

Two classes of organelles

A

Endomembrane system

Energy-related organelles

28
Q

Endomembrane system:

A

Organelles that communicate with one another
● Via membrane channels
●Via small vesicles

29
Q

Energy-related organelles

A

Mitochondria (Mitochondria are membrane-bound cell organelles that generate most of the chemical energy needed to power the cell’s biochemical reactions)& chloroplasts (the organelles responsible for photosynthesis)

Basically independent & self-sufficient

30
Q

Animal Cell Anatomy

A

A typical animal cell comprises the following cell organelles:

Cell Membrane

Nucleus

Nuclear Membrane

Centrosome

Lysosome

Cytoplasm

Golgi Apparatus
Mitochondrion

Ribosome

Endoplasmic Reticulum (ER)

Vacuole

Nucleopore

31
Q

Plant Cell Anatomy

A

Cell Wall

Cell membrane

Nucleus

Plastids

Central Vacuole

Golgi Apparatus

Ribosomes

Mitochondria

Lysosome

32
Q

Nucleus

A

Command center of cell, usually near the center
Separated from the cytoplasm by the nuclear envelope
Consists of double layer of membrane
Contains chromatin in semifluid nucleoplasm
Chromatin contains DNA and proteins
Condenses to form chromosomes during cell division
Dark nucleolus contains rRNA and proteins
Site of assembly of ribosome subunits

33
Q

Nucleus

A

Command center of cell, usually near the center

Separated from the cytoplasm by the nuclear envelope

Contains chromatin in semifluid nucleoplasm

Condenses to form chromosomes during cell division

34
Q

chromatin

A

Chromatin contains DNA and proteins

Condenses to form chromosomes during cell division

35
Q

Dark nucleolus contains

A

rRNA and proteins
Site of assembly of ribosome subunits

36
Q

rRNA

A

ribosomal RNA (rRNA), molecule in cells that forms part of the protein-synthesizing organelle known as a ribosome and that is exported to the cytoplasm to help translate the information in messenger RNA (mRNA) into protein

37
Q

Ribosomes

A

Are the site of protein synthesis in the cell

Consists of a large subunit and a small subunit

Each subunit is composed of rRNA and proteins

Subunits are assembled in the nucleolus

38
Q

Ribosomes May be located

A

On the endoplasmic reticulum (thereby making it “rough”),

or Free in the cytoplasm, either singly
or in groups, called polyribosomes

39
Q

The Endomembrane System

A

Series of intracellular membranes that compartmentalize the cell

● Restricts certain enzymatic reactions to specific compartments within the cell

40
Q

The Endomembrane System Consists of:

A
  1. Nuclear envelope
  2. Membranes of the endoplasmic reticulum
  3. Golgi apparatus
  4. Vesicles
    ● Several types
    ● Transport materials between organelles of system
41
Q

The Endoplasmic Reticulum

A

A system of membrane channels and saccules (flattened vesicles)

Continuous with the outer membrane of the nucleus

Rough ER

-Studded with ribosomes on the cytoplasmic side

-Synthesizes proteins

-Modifies and processes proteins
● Adds sugar to protein resulting in glycoproteins

42
Q

The Endoplasmic Reticulum

A

Smooth ER
-No ribosomes
-Site of lipid synthesis and certain detoxification reactions

Both rough and smooth ER forms transport vesicles to transport molecules

43
Q

The Endoplasmic Reticulum

A

Smooth ER
-No ribosomes
-Site of lipid synthesis and certain detoxification reactions

Both rough and smooth ER forms transport vesicles to transport molecules

44
Q

The Golgi Apparatus

A

Consists of a stack of 3-20 flattened, curved saccules

Resembles a stack of hollow pancakes

Modifies proteins and lipids

45
Q

Golgi Apparatus

A

Receives vesicles from ER on the cis (inner) face

Prepares proteins for “shipment” in vesicles

Packages proteins into vesicles at the trans (outer)

Vesicles have several destinations
Nucleus

Within cell (lysosomes, ER)
Export from cell (secretion, exocytosis)
46
Q

Golgi Apparatus

A

Receives vesicles from ER on the cis (inner) face

Prepares proteins for “shipment” in vesicles

Packages proteins into vesicles at the trans (outer)

Vesicles have several destinations
Nucleus

Within cell (lysosomes, ER)
Export from cell (secretion, exocytosis)
47
Q

Lysosomes

A

Membrane-bound vesicles

Produced by the Golgi apparatus

Contain powerful digestive enzymes and are highly acidic

  ● Digestion of large molecules and nonfunctional organelles
 ● Recycling of cellular resources
48
Q

Peroxisomes

A

Similar to lysosomes
Membrane-bounded vesicles

  Enclose enzymes

 Active in lipid metabolism

    Catalyze reactions that produce hydrogen peroxide H2O2
49
Q

Vacuoles

A

Membranous sacs that are larger than vesicles

  • Store materials that occur in excess
  • May be very specialized (contractile vacuole)
50
Q

contractile vacuole

A

A contractile vacuole works just the same as the name suggests, in that it expands and contracts. The function of the contractile vacuole is to pump water out of the cell through a process called osmoregulation, the regulation of osmotic pressure

51
Q

a central vacuole

A
  • Plants cells typically have a central vacuole
  • Up to 90% of the volume of some cells Functions in:
    ● Storage of water, nutrients, pigments, and waste products
    ● Development of turgor pressure
    ● Some functions performed by
    lysosomes in animal cells
52
Q

Chloroplasts

A
  • Membranous organelles that serve as the site of photosynthesis

-Chlorophyll and other pigments capture light energy Photosynthesis

  • Inner membrane is infolded
    Forms disc-like thylakoids, which are stacked to form grana
  • Green due to chlorophyll
53
Q

Photosynthesis

A

● Synthesizes carbohydrates from CO2 & H2O

54
Q

Inner membrane

A

-Forms disc-like thylakoids, which are stacked to form grana*

-Suspended in semi-fluid stroma

  • Grana are stacks of structures called thylakoids which are little discs of membrane on which the light-dependent reactions of photosynthesis take place
55
Q

thylakoids

A

Thylakoids are membrane-bound compartments inside chloroplasts and cyanobacteria.

They are the site of the light-dependent reactions of photosynthesis.

56
Q

chlorophyll

A

Green photosynthetic pigment

Found ONLY in the thylakoid
membranes of chloroplast

57
Q

Mitochondria

A

-Smaller than chloroplasts

-Contain ribosomes and their own DNA

  • Surrounded by a double membrane

-Involved in cellular respiration

-Produce most of the ATP* utilized by the cell

*ATP is commonly referred to as the “energy currency” of the cell, as it provides readily releasable energy in the bond between the second and third phosphate groups.

58
Q

Cytoskeleton

A
  • Maintains cell shape
  • Assists in movement of the cell and organelles
59
Q

Three types of macromolecular fibers

A
  • Actin Filaments
  • intermediate filaments
  • Microtubules
60
Q

Actin Filaments

A

-Two chains of extremely thin filaments twisted around each other

-Dense web just under the plasma membrane maintains cell shape

-Support for microvilli in intestinal cells

  • Pinch mother cell in two after animal mitosis
  • Important function in muscle contraction (along with myosin)
61
Q

microvilli

A

Microvilli ( sg. : microvillus) are microscopic cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume, and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction.

62
Q

myosin

A

Myosin is the prototype of a molecular motor—a protein that converts chemical energy in the form of ATP to mechanical energy, thus generating force and movement.

63
Q

Intermediate Filaments

A
  • Intermediate in size between actin filaments and microtubules
  • Rope-like assembly of fibrous polypeptides
  • Vary in nature
    +From tissue to tissue
    + From time to time
  • Functions:
    >Support nuclear envelope
    >Cell-cell junctions, like those holding skin cells tightly together
    >Include keratin*

*A type of protein found on epithelial cells, which line the inside and outside surfaces of the body. Keratins help form the tissues of the hair, nails, and the outer layer of the skin

64
Q

Microtubules

A

Hollow cylinders made of two globular proteins called α and β tubulin

Spontaneous pairing of α and β tubulin molecules forms dimers

Dimers then arrange themselves into tubular spirals of 13 dimers around an empty central core

Microtubules interact with the motor proteins kinesin and dynein to cause movement of organelles

65
Q

Microtubules Assembly

A

Under control of Microtubule Organizing Center (MTOC)

In most eukaryotic cells, the main MTOC is the centrosome*

  • A centrosome is a cellular structure involved in the process of cell division. Before cell division, the centrosome duplicates and then, as division begins, the two centrosomes move to opposite ends of the cell.

*

66
Q

Centrioles

A
  • Microtubular Arrays
  • Short, hollow cylinders
  • Composed of 27 microtubules
  • Microtubules are arranged into 9 overlapping triplets

-One pair per animal cell
- Located in the centrosome of animal cells
- Oriented at right angles to each other

Separate during mitosis*

  • Mitosis, a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells.
67
Q

Why is a small cell for exchaning molecules

A

Because of its greater surface area to volume ratio

BIO 201 (5 decks)

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