Cellular Structures

Question 1

are cell types found in organisms belonging to the domains Bacteria and Archaea whereas

Answer 1

Prokaryotic Cells

Question 2

are found in all organisms within the domain Eukarya—this includes the kingdoms Animalia,
Plantae, and Fungi

Answer 2

Eukaryotic Cells

Question 3

Irrespective of type, all cells contain a number of similar structural components that they share:

Answer 3

● All cells contain an outer covering called the plasma membrane. This structure separates the external environment from the complex processes and reactions taking place inside the cell.

● The cytoplasm is the area of the cell inside the plasma membrane but outside the nucleus. All other organelles, structures, and cellular materials are found here suspended in a semi-fluid liquid called the cytosol.

● All cells contain DNA, although it is organized differently between prokaryotes and eukaryotes. This is the genetic material that contains the instructions for all life’s
processes.

● Lastly are ribosomes. These structures convert nucleic acids into proteins, a key macromolecule in the structural formation of the cell.

Question 4

The DNA in prokaryotic cells is bundled up together in what is known as a

Answer 4

Nucleoid

Question 5

This structure forms an additional layer of protection maintains the cell shape and prevents the cell from dehydrating (Prokaryotic cells)

Answer 5

Cell wall

Question 6

These are compartmentalized structures that are able to perform more specific cellular processes. Some of these organelles have even originated from prokaryotic cells!

Answer 6

Membrane-bound organelles

Question 7

In eukaryotic cells, the DNA is packed inside a membrane-enclosed structure called the

Answer 7

Nucleus

Question 8

The fluid-filled space inside the nucleus is called
the

Answer 8

Nucleoplasm

Question 9

Together, the cytoplasm and
nucleoplasm are called the

Answer 9

Protoplasm

Question 10

The endomembrane system is an organellar system composed of three main membrane-bound organelles: ? These three work
together in order to secrete substances out of the cell.

Answer 10

the nucleus, endoplasmic reticulum, and the Golgi apparatus.

Question 11

-most prominent organellar structure you will find when looking at cells under a microscope

-often dubbed as the information center of the cell

Answer 11

The Nucleus

Question 11

two main functions of the nucleus

Answer 11

1. Directs chemical reactions in the cell by transcribing DNA into RNA, which is then translated into proteins
2. Stores genetic information which is duplicated and passed down during cellular reproduction

Question 12

Most of the cell’s DNA is found in the nucleus. Here, this macromolecule is loosely condensed
into long strands called

Answer 12

Chromatin

Question 13

During cellular division, the chromatin is duplicated,
condensed, and coiled into ? containing hereditary information that will be perpetuated for the continuation of life.

Answer 13

Chromosomes

Question 14

This is a non-membrane bound structure found in the nuclei of non-dividing cells.

produce ribosomes, and RNA-based organelle responsible for the translation of
RNA into proteins.

Answer 14

Nucleolus

Question 15

The membrane of this organelle is connected
to the nucleus to facilitate the production of
substances.

Answer 15

Endoplasmic Reticulum

Question 16

is described as such because it is studded with
many ribosomes in its membranes, whose role
is to produce proteins, much-like in
free-floating ribosomes.

Answer 16

Rough Endoplasmic Reticulum

Question 17

Responsible for the production of:

1. lipids (such as steroid hormones),
2. enzymes to detoxify drugs and poisons, and
3. in muscle cells, secrete calcium ions for muscle contraction

Answer 17

Smooth Endoplasmic Reticulum

Question 18

the ‘processing center’ of the endomembrane system; Once the products are ready, this sorts
and packages these into vesicles.

Answer 18

Golgi Apparatus

Question 19

This organelle ‘processes’ the
ER’s products in the following ways:

Answer 19

1. Proteins complete their tertiary or quaternary
   structures, becoming functional,
2. Carbohydrates are attached to lipids or
   proteins for recognition

Question 20

are spherical membrane-bound structures that
substances (in this case, the products of the
endomembrane system).

Answer 20

Vesicles

Question 21

Some vesicles in the endomembrane system remain in the cell; are produced by the Golgi apparatus, with enzymes originating from the ER. These spherical bodies act as ‘digestion centers’ of the cell, breaking down organic molecules that have been ‘eaten’ by the cell.

Answer 21

Lysosomes

Question 21

Some vesicles in the endomembrane system remain in the cell; are produced by the Golgi apparatus, with enzymes originating from the ER. These spherical bodies act as ‘digestion centers’ of the cell, breaking down organic molecules that have been ‘eaten’ by the cell.

Answer 21

Lysosomes

Question 22

are similar in structure with lysosomes
but originate entirely from the ER and not from the
golgi apparatus. This organelle protects the cell from
toxic substances, especially hydrogen peroxide
(usually in the mitochondria), which is harmful to cells
due to their reactivity.

Answer 22

Peroxisomes

Question 23

are membranous sacs with a variety of shapes and forms. They are very prominent in plants. However, in animals, vacuoles are smaller, serving as storage of organic compounds (such as food), or—in some animals, pump water out of a cell (such as the image to your right; an anima-like protist, called a Paramecium contains contractile vacuoles to pump water out)

Answer 23

Vacuoles

Question 24

Colloquially regarded as the ‘powerhouse of the cell’, this organelle is specifically the site for aerobic respiration. They are responsible for generating most of the cells energy currency: ATP. These organelles also have their own DNA and have once been an independent cell that have been assimilated into the eukaryotic structure millions of years ago.

Answer 24

Mitochondria

Question 25

are membrane-bound organelles that produce and store organic compounds. The most notable of these, are chloroplasts which undergoes photosynthesis. Some plastids store lipids, proteins or pigments. However, plastids are only found in autotrophic eukaryotes. Therefore, animals do not have plastids.

Answer 25

Plastids

Question 26

a network of proteins that provides the framework and structure to the cell, much like your skeleton is to your body.

Answer 26

Cytoskeleton

Question 27

Cytoskeletons are composed of three types of proteins:

Answer 27

microfilaments (green), actin filaments (red), and intermediate filaments (yellow).

Question 28

Functions of the cytoskeleton

Answer 28

Other than providing the structural framework of the cell, they also function in: 1. Providing mechanical resistance and strength to the cell 2. Aid in movement and contraction 3. Act as a ‘cellular highway’ for the movement of vesicles and substances

Question 29

Two associated structures of the cytoskeleton are responsible for much of the movement in some animal cells.

Answer 29

Cillia and Flagella

Question 30

are short, numerous filaments that coordinate in a sweeping motion

Answer 30

Cilia

Question 31

are long tail-like extensions that occur singly or in pairs.

Answer 31

Flagella

Question 32

These structures are produced by the active movement of the cytoskeleton and cytoplasm, generating

Answer 32

amoeboid movement

Question 33

Near the nucleus, at nonmembranous regions of the cytoplasm, are microtubule-organizing centers

Answer 33

Centrosomes

Question 34

a component of the cytoskeleton.

Answer 34

Microtubules

Question 35

are involved in the movement of chromosomes during cellular division

Answer 35

Centrioles

Question 36

functions as the main barrier between the internal and external environment of the cell. It also receives external stimuli from the environment and is responsible for the movement of materials into and out of the cell.

Answer 36

membranes (specifically the cell or plasma membrane)

Question 37

Cellular membranes are mainly composed of three structural components:

Answer 37

the phospholipid bilayer, cholesterol units, and membrane proteins (Carbohydrates are also present in the membrane but are often attached to lipids and proteins on the outer surface of the membrane.)

Question 38

The most prominent component of membranes is the ?. As the name implies, it is a double-layer of phospholipids. phospholipids are amphipathic, meaning that there is a hydrophilic(‘water-loving’) and hydrophobic (‘water-hating’) end. This is crucial in understanding how membranes are structured.

Answer 38

phospholipid bilayer

Question 39

These steroid molecules squeeze themselves in between the hydrophobic tails of the phospholipid bilayer, helping the phospholipids ‘jiggle’ and ‘move about’

Answer 39

Cholesterol

Question 40

as the ‘pieces float and swim about’ the phospholipid bilayer. Cholesterol helps maintain this fluidity of the cell membrane

Answer 40

fluid mosaic

Question 41

The ‘pieces’ that ‘float about’ in the membrane are mostly proteins called .

Answer 41

membrane proteins

Question 42

These proteins serve many functions for both the cell and the plasma membrane. Some of these include:

Answer 42

● Transporting materials through the membrane ● Facilitate in chemical reactions (as catalysts) ● Adheres cells together ● Receives external stimuli ● Provides cell-to-cell recognition