BIOLOGY UNIT 3
Jan 18, 2016
BIOLOGY UNIT 3
CELL THEORY All organisms are composed of cells
The cell is the smallest unit of living matter
Cells arise from pre-existing cells
Information is passed on to cells in the form of DNA
PROKARYOTIC v EUKARYOTIC
Prokaryotic Cells(Bacteria)
Eukaryotic Cells(Plants, Animals, Fungi, Protists)
Average diameter 0.5 – 5µm (10 times smaller in diameter) (100 – 1000 times smaller in volume) DNA is circular and lies free in the cytoplasm (circular chromosome in the nucleoid) (rings of accessory DNA called
plasmids) Smaller ribosomes NO Endoplasmic Reticulum (ER) NO MEMBRANE BOUND ORGANELLES Cell wall present (made of cross-linked
peptidoglycan) No true nucleus present Other structures may include: flagellum,
capsule, mesosome, pili)
Often up to 40 µm in diameter (size can vary) (10 times larger in diameter) (100 – 1000 times larger in
volume) DNA is not circular and is contained in the
nucleus (chromosomes) Larger ribosomes Endoplasmic Reticulum present (may contain
ribosomes) CONTAINS MEMBRANE BOUND
ORGANELLES single membrane eg: lysosomes, golgi body,
vacuoles double membrane eg: nucleus, mitochondria no membrane eg: ribosomes May have cell walls eg. Plants NUCLEUS present with nucleus containing
DNA
The Importance of compartmental organisationo Allows cells to carry out a variety of different functions at the same timeo The membranes of the organelles have important roles themselves and often contain many of the necessary proteins
• Characteristics of Prokaryotic Cells Characteristics of Eukaryotic Cells
Prokaryotic Cells Eukaryotic Cells
Cell Structure > Prokaryotic Cells
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PLANT CELLS v ANIMAL CELLS
Plant Cells Animal Cells NO CELL WALL NO CHLOROPLASTS MAY CONTAIN SMALLER
TEMPORARY VACUOLES
Mitochondria Cell Membrane Nucleus + Nucleolus Golgi Body ER Ribosomes Lysosomes Cytoplasm Centrioles
CELLULOSE CELL WALL CHLOROPLASTS (Containing
chlorophyll) LARGE PERMANENT VACUOLE Mitochondria Cell membrane Nucleus + Nucleolus Golgi Body ER Ribosomes Lysosomes Cytoplasm Centrioles
PLANT CELL
ANIMAL CELL
ORGANELLESCELL MEMBRANELOCATION: - surrounding the cell and below the
cell wall in plants
FUNCTION: - gives the cell shape and Protection from the exterior world. Regulates the movements of substances into and out of the cell. Has fluid type movement due to the PHOSPHOLIPID BILAYER and contains various proteins
PLANT CELLS:- Yes
ANIMAL CELLS:- Yes
LIGHT MICROSCOPE:- Yes
RIBOSOMES(no membranes)
LOCATION:- Free in the cytoplasm or attached to rough ER
FUNCTION:- Comprise of a complex ribosomal RNA and protein and are the site of polypeptide/protein synthesis
PLANT CELLS:- Yes
ANIMAL CELLS:- Yes
LIGHT MICROSCOPE:- No
Mitochondria
LOCATION:- In the cytoplasm enclosed by a double membrane
FUNCTION:- Responsible for energy production via ATP. Site of Kreb’s Cycle, Electron Transport Chain. Contain mitochondrial DNA. Matrix and folded cristae are sites for cellular respiration
PLANT CELLS:- Yes
ANIMAL CELLS:- Yes
LIGHT MICROSCOPE:- No (only very high powered light microscope)
Golgi Apparatus(single membrane)
LOCATION:- In the cytoplasm, associated with the smooth ER, often close to the nucleus
FUNCTION:- Flattened sacs (cisternae) are constantly being formed from one end by vesicles which bud off from the smooth ER and broken down at the other end to form Golgi vesicles. Collects, processes and sorts molecules (esp. Proteins and lipids) ready for transport in the Golgi vesicles. Used to make lysosomes.
PLANT CELLS:- Yes
ANIMAL CELLS:- Yes
LIGHT MICROSCOPE:- No (only very high powered light microscope)
ROUGH ENDOPLASMIC RETICULUMLOCATION:- Throughout the whole cytoplasm often closely associated with the nuclear envelope.
FUNCTION:- Rough endoplasmic reticulum houses ribosomes. Membranes form a system of flattened sacs (cisternae) which can go on to form the golgi apparatus. The rough ER transports proteins formed by ribosomes throughout the cell.
PLANT CELLS:- Yes
ANIMAL CELLS:- Yes
LIGHT MICROSCOPE:- No
CHLOROPLASTS(double membrane)
LOCATION:-Within the cytoplasm, particularly in the cells at the surface of leaves in plants
FUNCTION:- The site of photosynthesis. The light-dependant stage taking place in the thylakoids and involves the absorbtion of blue and red light wavelengths that eventually energise the electron transport system. The light-independant stage occurs in the stroma and produces sugar molecules via the Calvin-Benson cycle. Contains its own DNA.
PLANT CELLS:- YES
ANIMAL CELLS:- NO
LIGHT MICROSCOPE:- YES
CENTRIOLES
LOCATION:- Found in the cytoplasm, usually near the nucleus
FUNCTION:- Arranged at right angles to each other and comprising of microtubules. The centrioles help organise chromosomes via poles during cell replication. They ARE NOT found in most higher plants.
PLANT CELLS:- Variable (not in higher plants)
ANIMAL CELLS:- YES
LIGHT MICROSCOPE:- NO
CILIA & FLAGELLA
LOCATION:- Anchored in the cell membrane and extending outside of the cell
FUNCTION:- Flagella are often limited to 1 per cell and cilia may be many. They are structures used in locomotion, particularly in water
PLANT CELLS:- NO
ANIMAL CELLS:- YES
LIGHT MICROSCOPE:- Occasionally (depending on the preparation)
CELLULOSE CELL WALL
LOCATION:- Surrounds the plant cell and sits outside the plasma membrane
FUNCTION:- Provides rigidity and strength, supports the cell against changes in turgor (water pressure)
PLANT CELLS:- YES
ANIMAL CELLS:- NO
LIGHT MICROSCOPE:- YES
LYSOSOMES(single membrane)
LOCATION:- Throughout the cytoplasm
FUNCTION:- Contain digestive enzymes which aid in the digestion of foreign matter (eg. Bacteria) as well as the cells own organic material. The digestive enzymes function best at pH 5 (acidic) and therefore cause minor damage if small amounts are leaked. Large amounts may cause cell death via autodigestion
PLANT CELLS:- YES (variably, vacuoles have lysosomal function)
ANIMAL CELLS:- YES
LIGHT MICROSCOPE:- NO
VACUOLE(single membrane)
LOCATION:- Free in the cytoplasm
FUNCTION:- In plants they are large and permanent and involved in storage and support. In animal cells they are smaller and can be formed via phagocytosis (FOOD VACUOLES) to be then digested by lysosomes. Also used for storage of water, wastes and soluble pigments
PLANT CELLS:- YES (large & permanent)
ANIMAL CELLS:- YES (smaller & often numerous)
LIGHT MICROSCOPE:- YES (plant cell) NO (animal cell)
NUCLEUS(double membrane)
LOCATION:- within the cytoplasm, position variable
FUNCTION:- The control centre of the cell containing the nuclear material (DNA). Surrounded by a porous envelope, allowing RNA into and out of the nucleus.
PLANT CELLS:- YES
ANIMAL CELLS:- YES
LIGHT MICROSCOPE:- YES
Cell Surface Size
• Notice that as a cell increases in size, its surface area-to-volume ratio decreases.
• When there is insufficient surface area to support a cell's increasing volume, a cell will either divide or die.
• The cell on the left has a volume of 1 mm3 and a surface area of 6 mm2, with a surface area-to-volume ratio of 6 to 1,
V = lxwxh = 1x1x1 = 1mm3 SA = lxwx6 = 1x1x6 = 6mm2 SA:V = 6:1
• The cell on the right has a volume of 8 mm3 and a surface area of 24 mm2, with a surface area-to-volume ratio of 3 to 1.
V = lxwxh = 2x2x2 = 8mm3 SA = lxwx6 = 2x2x6 = 24mm2 SA:V = 24:8 = 3:1
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SURFACE AREA to VOLUME RATIO IN CELLS
SURFACE AREA to VOLUMEDue to Surface Area:Volume
Ratios, Cells are limited in their size.
The greater the volume of a cell the more requirements necessary. Howver, the surface area ratio will be lower and therefore exchanging materials with its surroundings will be less efficient. Meaning the cell cannot survive
The same principal applies to multi-cellular organisms that exchange materials (eg. O2/CO2) through their skin such as insects
This is why insects cannot be the size of an Elephant!
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Cell Structure
What makes an organism a prokaryote?
A) They have plasma membranes to protect them from their surrounding environment.
B) It's cellular components are found within cytoplasm.
C) Prokaryotes lack a membrane-bound nucleus and membranous organelles.
D) They contain DNA and ribosomes within the cell.
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Cell Structure
What makes an organism a prokaryote?
A) They have plasma membranes to protect them from their surrounding environment.
B) It's cellular components are found within cytoplasm.
C) Prokaryotes lack a membrane-bound nucleus and membranous organelles.
D) They contain DNA and ribosomes within the cell.
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Cell Structure
Which of the following is NOT a characteristic of prokaryotes?
A) DNA
B) cell membrane
C) cell wall
D) endoplasmic reticulum
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Cell Structure
Which of the following is NOT a characteristic of prokaryotes?
A) DNA
B) cell membrane
C) cell wall
D) endoplasmic reticulum
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Cell Structure
Which of the following is found both in eukaryotic and prokaryotic cells?
A) nucleus
B) vacuoles
C) mitochondrion
D) ribosomes
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Cell Structure
Which of the following is found both in eukaryotic and prokaryotic cells?
A) nucleus
B) vacuoles
C) mitochondrion
D) ribosomes
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Cell Structure
Eukaryotic cells contain the following:
A) all of these answers
B) a nucleus that is not surrounded by a membrane
C) circular chromosomal structures within a membrane-bound nucleus
D) structures that specialize in energy production
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Cell Structure
Eukaryotic cells contain the following:
A) all of these answers
B) a nucleus that is not surrounded by a membrane
C) circular chromosomal structures within a membrane-bound nucleus
D) structures that specialize in energy production
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Cell Structure
Which of the following are correct regarding diffusion through the lipid bilayer that makes up the plasma membrane?
A) Large particles cannot fit in between the individual phospholipids that are packed together.
B) Only materials that are relatively small and non-polar can go through easily.
C) Polar molecules are repelled by the non-polar lipids that line the inside of the bilayer.
D) All of these answers are correct.
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Cell Structure
Which of the following are correct regarding diffusion through the lipid bilayer that makes up the plasma membrane?
A) Large particles cannot fit in between the individual phospholipids that are packed together.
B) Only materials that are relatively small and non-polar can go through easily.
C) Polar molecules are repelled by the non-polar lipids that line the inside of the bilayer.
D) All of these answers are correct.
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Cell Structure
If the nucleolus were not able to carry out its function, which nucleus-synthesized organelles would be affected?
A) Proteins
B) Chromosomes
C) Ribosomes
D) DNA
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Cell Structure
If the nucleolus were not able to carry out its function, which nucleus-synthesized organelles would be affected?
A) Proteins
B) Chromosomes
C) Ribosomes
D) DNA
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Cell Structure
A primary function of the nucleus in eukaryotic cells is:
A) to produce ATP that powers the cell.
B) to synthesize proteins from mRNA.
C) to contain the cell's hereditary material.
D) to transport proteins outside of the cell.
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Cell Structure
A primary function of the nucleus in eukaryotic cells is:
A) to produce ATP that powers the cell.
B) to synthesize proteins from mRNA.
C) to contain the cell's hereditary material.
D) to transport proteins outside of the cell.
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Cell Structure
In mitochondria, the process of using oxygen and producing carbon dioxide as a waste product is due to what cellular reaction?
A) It is a by-product of cellular respiration.
B) It is due to mitochondria's generation of iron and sulfur clusters.
C) It is a result of important cofactors of many enzymes.
D) It is due to the associative reaction of anaerobic eukaryotes and aerobic prokaryotes.
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Cell Structure
In mitochondria, the process of using oxygen and producing carbon dioxide as a waste product is due to what cellular reaction?
A) It is a by-product of cellular respiration.
B) It is due to mitochondria's generation of iron and sulfur clusters.
C) It is a result of important cofactors of many enzymes.
D) It is due to the associative reaction of anaerobic eukaryotes and aerobic prokaryotes.
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Cell Structure
What is an important difference between plant cells and animal cells?
A) Heterotrophs capture light energy to produce their own food.
B) Animal and bacterial cells contain chlorophyll, but it is not bound within organelles.
C) Animal cells are able to capture light energy through stroma.
D) Plants are able to make their own food through the use of chloroplasts, which enable photosynthesis.
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Cell Structure
What is an important difference between plant cells and animal cells?
A) Heterotrophs capture light energy to produce their own food.
B) Animal and bacterial cells contain chlorophyll, but it is not bound within organelles.
C) Animal cells are able to capture light energy through stroma.
D) Plants are able to make their own food through the use of chloroplasts, which enable photosynthesis.
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Cell Structure
The smallest unit of biological structure that meets the functional requirements of “living” is the ________.
A) organ
B) organelle
C) cell
D) macromolecule
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Cell Structure
The smallest unit of biological structure that meets the functional requirements of “living” is the ________.
A) organ
B) organelle
C) cell
D) macromolecule
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Cell Structure
The ________ is the basic unit of life.
A) organism
B) cell
C) tissue
D) organ
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Cell Structure
The ________ is the basic unit of life.
A) organism
B) cell
C) tissue
D) organ
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Cell Structure
Which of the following best describes traits associated with an electron microscope?
A) The microscope stains the electrons in a specimen.
B) The microscope uses visible light to identify cell structures.
C) The microscope allows for a maximum magnification of 1000 times the original size.
D) The microscope uses a beam of electrons to provide high resolving power and high magnification.
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Cell Structure
Which of the following best describes traits associated with an electron microscope?
A) The microscope stains the electrons in a specimen.
B) The microscope uses visible light to identify cell structures.
C) The microscope allows for a maximum magnification of 1000 times the original size.
D) The microscope uses a beam of electrons to provide high resolving power and high magnification.
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Cell Structure
Which of the following is a core component of the cell theory?
A) All energy flow occurs within the cell.
B) The cell is the basic unit of life.
C) Both the cell is the basic unit of life and all new cells arise from existing cells.
D) All new cells arise from existing cells.
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Cell Structure
Which of the following is a core component of the cell theory?
A) All energy flow occurs within the cell.
B) The cell is the basic unit of life.
C) Both the cell is the basic unit of life and all new cells arise from existing cells.
D) All new cells arise from existing cells.