Cell Structure And Function

Front 1

mitochondria

Back 1

A spherical or rod-shaped organelle found within the cytoplasm of eukaryotic cells. It acts as the “powerhouse of the cell” as it generates most of the cell's supply of adenosine triphosphate (ATP) through the process of cellular respiration.

Front 2

What is the structure of the mitochondria?

Back 2

consists of outer and inner membranes, an intermembrane space (space in between the membranes), the cristae (infoldings of the inner membrane), and the matrix (space within the inner membrane). The outer membrane contains several porins that form channels where certain molecules can freely diffuse.

Front 3

Describe the outer membrane of a mitochondria

Back 3

-contains several porins that form channels where certain molecules can freely diffuse.

Front 4

Describe the inner membrane of the mitochondria

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-does not contain porins and is highly impermeable to all molecules. Most ions and molecules would need special membrane transporters to enter or exit the matrix.

Front 5

What is the function of the cristae?

Back 5

-increase the surface area within the mitochondria, thereby increasing ATP production

Front 6

Why is the mitochondria considered to be a semi-autonomous, self-reproducing structure?

Back 6

Because it contains its own genetic material, and is capable of manufacturing its own RNAs and proteins

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Cytoplasm

Back 7

In eukaryotic cells, the cytoplasm is that part of the cell between the cell membrane and the nuclear envelope. It is the jelly-like substance in a cell that contains the cytosol, organelles, and inclusions, but not including the nucleus.

Front 8

What is the function of the Golgi apparatus?

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-packaging of molecules like proteins into vesicles for secretion
-transport of lipids around the cell
-the creation of lysosomes

Front 9

What is the structure of the Golgi Apparatus?

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composed of membrane-bound stacks known as cisternae

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Endoplasmic Reticulum

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-interconnected flattened sacs or tubules that connect to the nuclear membrane, run through the cytoplasm, and may extend into the cell membrane.

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Rough Endoplasmic Reticulum

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-bears many ribosomes on its outer surface giving it a rough appearance
-involved in protein synthesis and secretion.

Front 12

Give an example of Rough Endoplasmic Reticulum being involved in Protein Synthesis

Back 12

It synthesizes and secretes serum proteins (such as albumin) in the liver, and hormones (such as insulin) and other substances (such as milk) in the glands.

Front 13

What is the function of Smooth Endoplasmic Reticulum

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synthesis of lipids,
-metabolism of carbohydrates and calcium concentration
-drug detoxification
-attachment of receptors on cell membrane proteins.
-involved in intracellular transport, such as the transport of the products of the RER to other cell parts like Golgi apparatus.

Front 14

Vesicle

Back 14

A bubble-like membranous structure that stores and transports cellular products, and digests metabolic wastes within the cell; an intracellular membranous sac that is separated from the cytosol by at least one lipid bilayer.

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Nucleus

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The large, membrane-bounded organelle that contains the genetic material, in the form of multiple linear DNA molecules organized into structures called chromosomes.

Front 16

What are the functions of the nucleus?

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-maintain the integrity of DNA
-to control cellular activities such as metabolism, growth, and reproduction by regulating gene expression.

Front 17

List and describe the three components of the nucleus

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-Nucleolus-The round granular structure within the nucleus of a cell, and composed of protein and RNA.
-chromatin-A complex of nucleic acids and proteins (histones), which condenses to form a chromosome during cell division.
-Nuclear envelope-has nuclear pores to control the movement of molecules between the nucleoplasm and the cytoplasm.

Front 18

What is the function of the nucleolus?

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-involved with ribosomal RNA synthesis and formation of ribosomes in eukaryotes.

Front 19

What is the function of Chromatin?

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package DNA into a smaller volume to fit in the cell, strengthen the DNA to allow mitosis and meiosis, and to serve as a mechanism to control expression.

Front 20

Cell membrane

Back 20

involved with ribosomal RNA synthesis and formation of ribosomes in eukaryotes.

Front 21

What is the function of the cell membrane?

Back 21

-controls which substances can go in and out of the cell.
-cell adhesion
-ion channel conductance
-cell signaling
-attachment point for cytoskeleton (which keeps the shape of the cell).

Front 22

What is a "cell signature?"

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-refers to the presence of original surface molecules that is thought to partake in the role of cell recognition.

Front 23

Lysosomes

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-Membranous sacs that contain digestive enzymes

Front 24

The cell membrane is "selectively permeable." What does this mean?

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-allows only selected materials to pass in and out of a cell (keeps foreign entities out, but cytoplasm in)

Front 25

What are the three methods in which ions are transported through the cell membrane into the cell?

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Active Transport, Passive Transport and Simple Diffusion.

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Active Transport

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Active transport is the transport of molecules with the active assistance of a carrier that can transport the material against a natural concentration gradient.

Front 27

Passive Transport

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The movement of molecules from areas of high concentration to areas of low concentrationvia a carrier. This process does not require energy.

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Simple Diffusion

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The movement of molecules from areas of high concentration to areas of low concentration in a free state.

Front 29

Osmosis

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Simple diffusion of water through a selectively permeable membrane

Front 30

Pinocytosis

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A process of taking in fluid together with its contents into the cell by forming narrow channels through its membrane that pinch off into vesicles, and fuse with lysosomes that hydrolyze or break down contents.

Front 31

Phagocytosis

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The process of engulfing and ingestion of particles by the cell or a phagocyte, to where the engulfed material is eventually digested or degraded and either released extracellularly via exocytosis, or released intracellularly to undergo further processing.
-the mechanism used by many protists to acquire nutrients

Front 32

ATP

Back 32

-Adenosine Tri-Phosphate
-the energy used by an organism in its daily operations.
-consists of an adenosine molecule and three inorganic phosphates

Front 33

How do we create energy from ATP?

Back 33

-This is done by a simple process, in which one of the phosphate molecules is broken off, therefore reducing the ATP from 3 phosphates to 2, forming ADP
-When the bond connecting the phosphate is broken, energy is released

Front 34

What are the three steps that occur within cell respiration?

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* Glycolysis
* The Kreb's Cycle
* The Cytochrome System

Front 35

What is cell respiration?

Back 35

-Respiration involves the oxidation of foodstuff in order to create ATP.
-can occur with or without oxygen, (aerobic and anaerobic respiration)

Front 36

Glycolysis

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-Glycolysis occurs in the cytoplasm of a cell where a 6 carbon glucose molecule is broken down by enzymes into a 3 carbon pyruvic acid.
-In anaerobic respiration, this is where the process ends, glucose is split into 2 molecules of pyruvic acid.

Front 37

Kreb's Cycle

Back 37

-When oxygen is present, respiration can harness more ATP from a single unit of glucose. The pyruvic acid from the glycolysis stage diffuses into a mitochondrion.
-The pyruvic acid is then subject to more enzymes which break it down into a 2 carbon compound
* The carbon element is in an infinite cycle where the 2 carbon compound derived from pyruvic acid binds with the 4 carbon compound that is always present in the cycle.
* CO2 is released, where the oxygen that is present in aerobic respiration combines with carbon from the carbon compounds which is released as CO2. Hence the need for animals to breath out and expel this CO2.
* Enzymes oxidize the carbon compounds and transport the hydrogen atoms to the cytochrome system.

Front 38

What is the Cytochrome System also known as?

Back 38

The hydrogen carrier system or the electron transport system

Front 39

Describe the Process of the Cytochrome System

Back 39

-found in the many cristae of mitochondria
-Some coenzymes from earlier stages (we shall call these A) are transferred to the next coenzymes (refer to them as B).
-B is then oxidised, therefore the coenzyme releases the hydrogen and energy is made available.
-The released hydrogen atom binds with 2 oxygen atoms (oxygen is available in aerobic respiration) which produces water, a by-product of respiration.

Front 40

Chromosome

Back 40

-composed of DNA
-determine the structure, type and function of a cell

Front 41

Phagocytosis

Back 41

The process of engulfing and ingestion of particles by the cell or a phagocyte, to where the engulfed material is eventually digested or degraded and either released extracellularly via exocytosis, or released intracellularly to undergo further processing.
-the mechanism used by many protists to acquire nutrients

Front 42

ATP

Back 42

-Adenosine Tri-Phosphate
-the energy used by an organism in its daily operations.
-consists of an adenosine molecule and three inorganic phosphates

Front 43

How do we create energy from ATP?

Back 43

-This is done by a simple process, in which one of the phosphate molecules is broken off, therefore reducing the ATP from 3 phosphates to 2, forming ADP
-When the bond connecting the phosphate is broken, energy is released

Front 44

What are the three steps that occur within cell respiration?

Back 44

* Glycolysis
* The Kreb's Cycle
* The Cytochrome System

Front 45

What is cell respiration?

Back 45

-Respiration involves the oxidation of foodstuff in order to create ATP.
-can occur with or without oxygen, (aerobic and anaerobic respiration)

Front 46

Glycolysis

Back 46

-Glycolysis occurs in the cytoplasm of a cell where a 6 carbon glucose molecule is broken down by enzymes into a 3 carbon pyruvic acid.
-In anaerobic respiration, this is where the process ends, glucose is split into 2 molecules of pyruvic acid.

Front 47

Kreb's Cycle

Back 47

-When oxygen is present, respiration can harness more ATP from a single unit of glucose. The pyruvic acid from the glycolysis stage diffuses into a mitochondrion.
-The pyruvic acid is then subject to more enzymes which break it down into a 2 carbon compound
* The carbon element is in an infinite cycle where the 2 carbon compound derived from pyruvic acid binds with the 4 carbon compound that is always present in the cycle.
* CO2 is released, where the oxygen that is present in aerobic respiration combines with carbon from the carbon compounds which is released as CO2. Hence the need for animals to breath out and expel this CO2.
* Enzymes oxidize the carbon compounds and transport the hydrogen atoms to the cytochrome system.

Front 48

What is the Cytochrome System also known as?

Back 48

The hydrogen carrier system or the electron transport system

Front 49

Describe the Process of the Cytochrome System

Back 49

-found in the many cristae of mitochondria
-Some coenzymes from earlier stages (we shall call these A) are transferred to the next coenzymes (refer to them as B).
-B is then oxidised, therefore the coenzyme releases the hydrogen and energy is made available.
-The released hydrogen atom binds with 2 oxygen atoms (oxygen is available in aerobic respiration) which produces water, a by-product of respiration.

Front 50

Chromosome

Back 50

-composed of DNA
-determine the structure, type and function of a cell
-found in the nucleus

Front 51

DNA

Back 51

deoxyribonucleic acid

Front 52

Nucleotide

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-The basic building block of nucleic acids
-organic compound made up of nitrogenous base, a sugar, and a phosphate group.

Front 53

What are the four different types of nucleotides found in a DNA sequence?

Back 53

-adenine
-cytosine
-guanine
-thymine

Front 54

Of the four different types of nucleotides, which can be paired together to create a base pair?

Back 54

Adenine and thymine
cytosine and guanine

Front 55

In order for exact replication of DNA, what must be available?

Back 55

* The actual DNA to act as an exact template
* A pool of relevant and freely available nucleotides
* A supply of the relevant enzymes to stimulate reaction
* ATP to provide energy for these reactions

Front 56

Describe the replication of DNA

Back 56

-When replicating, the double helix structure uncoils so that each strand of DNA can be exposed. -When they uncoil, the nucleotides are exposed so that the freely available nucleotides can pair up with them.
-When all nucleotides are paired up with their new partners, they re-coil into the double helix.
-As there are two strands of DNA involved in replication, the first double helix produces 2 copies of itself via each strand.

Front 57

Why is it said that replicated DNA is "semi-conservative?"

Back 57

because it possesses 50% of the original genetic material from its parent

Front 58

Protein

Back 58

A molecule composed of polymers of amino acids joined together by peptide bonds. It can be distinguished from fats and carbohydrates by containing nitrogen. Other components include carbon, hydrogen, oxygen, sulphur, and sometimes phosphorus.

Front 59

What are some protein functions?

Back 59

serve as a structural material (e.g. keratin)
-as enzymes
-as transporters (e.g. hemoglobin), -as antibodies
-as regulators of gene expression.

Front 60

mRNA

Back 60

-messenger ribonucleic acid that transfer genetic information from the nucleus to the ribosomes of the Rough Endoplasmic Reticulum?

Front 61

How does mRNA differ from DNA?

Back 61

-similar to DNA, but fundamentally differs in two ways
* A base called uracil replaces all thymine bases in mRNA.
* The deoxyribose sugar in DNA in is replaced by ribose sugar in mRNA.

Front 62

Describe the role of mRNA in protein synthesis.

Back 62

-as in DNA replication the double helix uncoils, but the mRNA makes a replication of it substituting uracil for thymine
-the mRNA then moves out of the nucleus toward the ribosomes
-met in the ribosome by complimentary tRNA anticodons, which have opposing bases to that of the mRNA strand (the codons).
-Thesanticodons have an amino acid sequence to successfully code for a particular amino acid.

Front 63

Codon

Back 63

A set of three adjacent nucleotides, also called triplet, in mRNA that base-pair with the corresponding aniticodon of tRNA molecule that carries a particular amino acid,

Front 64

Amino acid

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The building block of protein in which each is coded for by a codon and linked together through peptide bonds.

Front 65

Peptide

Back 65

Any compound consisting of two or more amino acids.

Front 66

What determines the type of Protein?

Back 66

The sequence of amino acids

Front 67

Name and describe three types of Proteins.

Back 67

Fibrous Proteins - These fibre like proteins are used for structural purposes in organisms. This is because fibrous proteins are arranged in long strands and are insoluble in water.
-Globular Proteins - The polypeptide chains in globular proteins are folded together into a knot like shape that contains Enzymes, Hormones, Antibodies and Structural Proteins
-Conjugated Proteins - Conjugated proteins are essentially globular proteins that possess non-living substances, such as the haem found in haemoglobin, which possesses iron (a non-living substance)

Front 68

Lysozyme

Back 68

is an enzyme found in tears and saliva that has powerful digestive capabilities, and can break down foreign agents to a harmless status before they enter the body.

Front 69

Interferons

Back 69

-a family of proteins that are released by a cell that is under attack by an antigen.
-These interferons attach themselves to receptors on the plasma membrane of other cells
-This tells these neighbouring cells that an antigen is nearby and instructs them to begin coding for antiviral proteins
-this defends the cell by shutting it down. Any invading antigen will not be able to replicated its DNA (or mRNA) and protein coat inside the cell, effectively preventing the spread of it in the organism

Front 70

Lymphocytes

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-a type of white blood cell capable of producing a specific immune response to unique antigens. Some of these lymphocytes are capable of entrapping antigens on their surface.

Front 71

What happens to the antigens trapped on the surface of a lymphocyte?

Back 71

-they begin to code for unique antibodies, structures that are capable of catching these antigens.
-The lymphocytes code for a particular antibody on response to a particular antigen. The antibody that is formed will be capable of catching free antigens therefore neutralizing the threat.

Front 72

Name and describe two different lymphocytes

Back 72

-B Lymphocytes-produce free moving antibodies
-T lymphocytes-produce antibodies on their surface.

Front 73

Active Immunity

Back 73

-Vaccines are used for health purposes to expose our bodies to a particular antigen.
-These antigens are usually killed or severely weakened to decrease their potency.
-After destroying these pathogens, the body stores some T cells as memory cells, due to the fact they code for a particular antigen .
-This memory in T cells can be a means of artificially acquiring immunity
-a genuine attack by a pathogen is a naturally acquired type of immunity.

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Passive Immunity

Back 74

immunity to particular antigens as a result of genetic traits passed on from parents rendering the offspring immune to a particular pathogenic threat.