BIOL1003 Lecture Notes - Lecture 2: Anaerobic Respiration, Cellular Respiration, Ribosomal Rna
19 May 2018
School
Department
Course
Professor
Describe the structures and functions of a cell
Organelles
Location
Functions
Nucleus
Often near centre
of the cell
Directs cell's life processes
-
Contains genetic material of cell -
chromosomes and DNA
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Contains one or more nucleoli
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Nuclear membrane
Surrounds nucleus
Separates nucleus from cytoplasm
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Controls the highly selective two-exchange
between the nucleus and cytoplasm
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Nucleolus
In nucleus
Ribosomal RNA is synthesised and combined
with proteins
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Cytoplasm
Fills cell
Semi-fluid material in which the organelles are
found
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Cell/plasma
membrane
Regulates movement of substances into and
out of the cell
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Mitochondrion
In cytoplasm
Cellular respiration (aerobic)
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Produce energy in the form of ATP, site of ATP
of synthesis
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Rough endoplasmic
reticulum
In cytoplasm
Site of protein synthesis and transport
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Rough texture due to ribosomes on surface
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Smooth
endoplasmic
reticulum
In cytoplasm
Site of lipid synthesis
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Participates in detoxification of toxins
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Golgi body
Storage, modification and packaging of
secretory products
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Lysosome
Contains hydrolytic enzymes
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Cellular digestion
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Ribosome
Protein synthesis
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Centrioles
Cell division
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Formation of spindle fibers that separate
chromosomes during cell division/mitosis
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2.1
Wednesday, 15 March 2017
10:12 PM
2. Cell structure Page 1
Explain surface area to volume ratios in relation to cells.
SA/V
Rate of diffusion into or out of cell decreases as the cell increases in size, as there is less
surface area per unit of volume across which to exchange substances
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Rate of diffusion and SA/V ratio
Determined by rate of diffusion of nutrients and gases across the cell surface
-
Cell can increase max size by developing an intracellular transport system (membrane
systems), compartmentalize processes e.g. organelles
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Max size to which a cell can grow
Relationship between SA and V applies also to substances transported in an organism or
across a cell membrane e.g. water, oxygen, wastes
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Small cells have a large SA:V ratio compared to large cells
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As cell size increases, the rate of mvt of substances across the surface becomes insufficient to
serve all the volume of the cell
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IN CELLS
- larger cells have a lower SA:V ratio so overall heat loss relative to surface area will be lower than
that of SMALLER cells
Metabolism is the sum of the chemical changes that occur in tissues, consisting of the
breakdown of molecules to produce energy and the build-up of molecules which requires
energy.
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Energy released from breakdown of food molecules is used to produce ATP
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Aerobic respiration - when oxy avail
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Anaerobic respiration - when oxy not avail, produces lactic acid in animals
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Cell metabolism
2.2
Friday, 17 March 2017
2:27 PM
2. Cell structure Page 2
Explain the evidence that DNA encodes genetic
information
Genes = Hereditary "factors" causing different traits, physical nature unknown
•
Genes carried on chromosomes
•
Chromosomes consist of protein and DNA
•
Proteins = key components of organisms, 20 amino acids known
•
DNA known to consist of 4 nucleotides, STRUCTURE unknown
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Genes 1940-50
Griffith's work on Streptococcus pneumoniae (1928)
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Avery et al. prove DNA carries genetic information (1944)
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Experiments showing DNA was hereditary material, genes made of DNA
DNA has only 4 nucleotides = too simple to encode proteins
○
Proteins contain 20 amino acids
○
Proteins make diverse and complex materials e.g. hair, skin, enzymes
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Protein likely to be hereditary material
○
Linus Pauling
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Key people
2.3
Saturday, 25 March 2017
10:54 PM
2. Cell structure Page 3
Document Summary
Describe the structures and functions of a cell. Contains genetic material of cell - chromosomes and dna. Controls the highly selective two-exchange between the nucleus and cytoplasm. Ribosomal rna is synthesised and combined with proteins. Semi-fluid material in which the organelles are found. Regulates movement of substances into and out of the cell. Produce energy in the form of atp, site of atp of synthesis. Formation of spindle fibers that separate chromosomes during cell division/mitosis: cell structure page 1. Explain surface area to volume ratios in relation to cells. Rate of diffusion into or out of cell decreases as the cell increases in size, as there is less surface area per unit of volume across which to exchange substances. Max size to which a cell can grow. Determined by rate of diffusion of nutrients and gases across the cell surface. Cell can increase max size by developing an intracellular transport system (membrane systems), compartmentalize processes e. g. organelles.
