Cells Lecture Summaries:
Define the following terms:
- Atom
- Smallest stable units
- Element
- Pure substance, consisting only of atoms with same atomic no.
- Molecule
- Atoms joined by bonds, elements & molecules
Describe the function and structure of the following:
- Carbohydrates
- Function:
- Energy storage, containing organic molecules, 1% TBW
- Structure:
- Sugars and starches made of C, O, H
- Lipids
- Function:
- Organic molecules, Fats/waxes/oils, energy (fat)
- Structure:
- Structural components of the cell membrane, C, O, H
- 12-19% TBW (M), 18-24% TBW (F)
- Nucleic Acids
- Function:
- Make RNA & DNA, genetic code, Organic molecules
- Structure:
- C, O, H, N, P
- Proteins
- Function:
- Support, movement, transport, buffer, metabolic regulation (growth),
coordination and control, defence (antibody)
- Structure:
- Organic molecules, containing C, O, H, N
- 16-20% TBW
What are the main constituents of the cell?
- Carbohydrates, lipids, protein, nucleotides, ions and water
What is the function of the nucleus - Describe the structure and all of its components?
- Function:
, - Control centre of the cell
- Houses genetic material
- Regulates expression of genes
- Activation/and or suppression, produces ribosomal units (exports to
cytoplasm)
- Structure:
- Most prominent feature of the cell
- Few cells have multiple nuclei (i.e. skeletal muscle cells) but majority have
one.
- Nuclear envelope: Double membrane, openings in envelope (nuclear pores),
continuous rough ER
- Nucleolus: Spherical, dark body found within nucleus, no membrane, site of
rRNA synthesis & initial ribosome assembly, obvious in cells that are actively
synthesising proteins
- Chromatin: Compacted DNA (DNA wrapped in around histone); packed into
chromatin. Euchromatin → Dispersed, lightly stained, active.
Heterochromatin → Highly condensed, intensely stained, INACTIVE cell.
Define the process of:
- Transcription
- DNA uncoils, Gene sequence is exposed (gene activation), mRNA strand is
assembled by enzymes/free nucleotides bind with complementary free
exposed DNA, generated mRNA sequence is complementary to DNA.
- Translation
- Occurs in the cytoplasm, mRNA decoded by ribosomes, amino acids align
attached to tRNA molecules to make specific protein
- INITIATION: mRNA enters the cytoplasm and binds to a ribosomal unit, tRNA
delivers specific amino acids (building blocks)
- ELONGATION: Amino acids are linked to form a polypeptide chain (protein)
- TERMINATION: Proteins are released and further modified.
Describe the structure and function of:
- Cytosol
- Structure:
- Intracellular fluid (fluid portion that surrounds organelles) 55% total cell
volume, varies in composition in consistency ~ 75-90% water, 10-25%
dissolved and suspended ions
- Functions:
- Water based solution by which organelles, proteins and other cell structures
float.
- Ribosomes
- Function:
, - Site of production of protein synthesis
- High content of RNA
- Structure:
- Consists of two subunits made in the nucleus, large and small subunit
- Some attached to rough ER, free ribosomes produce proteins in
cytosol
- Rough and smooth endoplasmic reticulum
- Function (rough ER):
- Protein synthesised here enter spaces in ER for processing and
sorting
- Structure (rough ER):
- Continuous with nuclear envelope
- Studded with ribosomes
- Function (smooth ER):
- Specialized function depending on location
- Produces hormones or lipids
- Structure (smooth ER):
- Lacks ribosomes
- Contains unique enzymes that synthesize fatty acids and steroids
- Golgi complex
- Structure:
- 3-20 cisternae
- Entry face on rER surface (cis cisternae)
- Exit face in plasma membrane surface (trans cisternae)
- Function:
- Most proteins synthesised on rER transported to other regions of the
cell, all passing through the golgi.
- Vesicles:
- Structure:
- Membrane bound organelles
- Continuously formed
- Function:
- Carrier (transport)/delivery (secretory) vesicles
- Contain: water, protein, enzyme, hormones
- Mitochondria
- Structure:
- Numbers vary 100 -1000’s depending
- Double membrane bound organelle with own DNA
, - Can self replicate - binary fission
- Inner folds (inward) called cristae
- Inner space called matrix
- Function:
- Cellular respiration occurs here
- Site of ATP production (energy within cell)
- Lysosomes
- Structure:
- Membrane enclosed vesicle
- Formed from golgi complex
- Contains as many as 60 enzymes
- Function:
- Breaks down molecules, digestion
- Helps recycle worn out parts
- Autography digestion of other organelles
- Works best in pH 5
- Cytoskeleton
- Structure:
- Skeletal/framework of the cell
- Function:
- Provides strength
- Shape
- Structural support and flexibility
- Labile continually remodelled
- Made in filamentous proteins
- Enable movement
- Microvilli, cilia, flagella
- Structure (Microvilli):
- Numerous, short extensions
- Function (Microvilli):
- Increase surface area
- Digestive tract
- Projections extending from the cells surface
- Aid movement
- Structure (Cilia):
- Hair-like projections
- Function (Cilia):
- Grow on top of the cell
- Move fluid along cell surface
- Digestive tract
- Structure (Flagella):
- Similar in structure to cilia, but much longer
- Function (Flagella):
- Moves entire cell
- Sperm
What are the main roles of the cell membrane?
- Function:
Define the following terms:
- Atom
- Smallest stable units
- Element
- Pure substance, consisting only of atoms with same atomic no.
- Molecule
- Atoms joined by bonds, elements & molecules
Describe the function and structure of the following:
- Carbohydrates
- Function:
- Energy storage, containing organic molecules, 1% TBW
- Structure:
- Sugars and starches made of C, O, H
- Lipids
- Function:
- Organic molecules, Fats/waxes/oils, energy (fat)
- Structure:
- Structural components of the cell membrane, C, O, H
- 12-19% TBW (M), 18-24% TBW (F)
- Nucleic Acids
- Function:
- Make RNA & DNA, genetic code, Organic molecules
- Structure:
- C, O, H, N, P
- Proteins
- Function:
- Support, movement, transport, buffer, metabolic regulation (growth),
coordination and control, defence (antibody)
- Structure:
- Organic molecules, containing C, O, H, N
- 16-20% TBW
What are the main constituents of the cell?
- Carbohydrates, lipids, protein, nucleotides, ions and water
What is the function of the nucleus - Describe the structure and all of its components?
- Function:
, - Control centre of the cell
- Houses genetic material
- Regulates expression of genes
- Activation/and or suppression, produces ribosomal units (exports to
cytoplasm)
- Structure:
- Most prominent feature of the cell
- Few cells have multiple nuclei (i.e. skeletal muscle cells) but majority have
one.
- Nuclear envelope: Double membrane, openings in envelope (nuclear pores),
continuous rough ER
- Nucleolus: Spherical, dark body found within nucleus, no membrane, site of
rRNA synthesis & initial ribosome assembly, obvious in cells that are actively
synthesising proteins
- Chromatin: Compacted DNA (DNA wrapped in around histone); packed into
chromatin. Euchromatin → Dispersed, lightly stained, active.
Heterochromatin → Highly condensed, intensely stained, INACTIVE cell.
Define the process of:
- Transcription
- DNA uncoils, Gene sequence is exposed (gene activation), mRNA strand is
assembled by enzymes/free nucleotides bind with complementary free
exposed DNA, generated mRNA sequence is complementary to DNA.
- Translation
- Occurs in the cytoplasm, mRNA decoded by ribosomes, amino acids align
attached to tRNA molecules to make specific protein
- INITIATION: mRNA enters the cytoplasm and binds to a ribosomal unit, tRNA
delivers specific amino acids (building blocks)
- ELONGATION: Amino acids are linked to form a polypeptide chain (protein)
- TERMINATION: Proteins are released and further modified.
Describe the structure and function of:
- Cytosol
- Structure:
- Intracellular fluid (fluid portion that surrounds organelles) 55% total cell
volume, varies in composition in consistency ~ 75-90% water, 10-25%
dissolved and suspended ions
- Functions:
- Water based solution by which organelles, proteins and other cell structures
float.
- Ribosomes
- Function:
, - Site of production of protein synthesis
- High content of RNA
- Structure:
- Consists of two subunits made in the nucleus, large and small subunit
- Some attached to rough ER, free ribosomes produce proteins in
cytosol
- Rough and smooth endoplasmic reticulum
- Function (rough ER):
- Protein synthesised here enter spaces in ER for processing and
sorting
- Structure (rough ER):
- Continuous with nuclear envelope
- Studded with ribosomes
- Function (smooth ER):
- Specialized function depending on location
- Produces hormones or lipids
- Structure (smooth ER):
- Lacks ribosomes
- Contains unique enzymes that synthesize fatty acids and steroids
- Golgi complex
- Structure:
- 3-20 cisternae
- Entry face on rER surface (cis cisternae)
- Exit face in plasma membrane surface (trans cisternae)
- Function:
- Most proteins synthesised on rER transported to other regions of the
cell, all passing through the golgi.
- Vesicles:
- Structure:
- Membrane bound organelles
- Continuously formed
- Function:
- Carrier (transport)/delivery (secretory) vesicles
- Contain: water, protein, enzyme, hormones
- Mitochondria
- Structure:
- Numbers vary 100 -1000’s depending
- Double membrane bound organelle with own DNA
, - Can self replicate - binary fission
- Inner folds (inward) called cristae
- Inner space called matrix
- Function:
- Cellular respiration occurs here
- Site of ATP production (energy within cell)
- Lysosomes
- Structure:
- Membrane enclosed vesicle
- Formed from golgi complex
- Contains as many as 60 enzymes
- Function:
- Breaks down molecules, digestion
- Helps recycle worn out parts
- Autography digestion of other organelles
- Works best in pH 5
- Cytoskeleton
- Structure:
- Skeletal/framework of the cell
- Function:
- Provides strength
- Shape
- Structural support and flexibility
- Labile continually remodelled
- Made in filamentous proteins
- Enable movement
- Microvilli, cilia, flagella
- Structure (Microvilli):
- Numerous, short extensions
- Function (Microvilli):
- Increase surface area
- Digestive tract
- Projections extending from the cells surface
- Aid movement
- Structure (Cilia):
- Hair-like projections
- Function (Cilia):
- Grow on top of the cell
- Move fluid along cell surface
- Digestive tract
- Structure (Flagella):
- Similar in structure to cilia, but much longer
- Function (Flagella):
- Moves entire cell
- Sperm
What are the main roles of the cell membrane?
- Function:
