IQ1 - Cells as the basis of life Flashcards
What are five differences between prokaryotic and eukaryotic cells?
Prokaryotic: unicellular, no nucleus, free floating DNA, circular DNA called plasmids, smaller, asexual reproduction
Eukaryotic: multicellular, larger, more complex, DNA organized into linear chromosomes, nucleus present, membrane bound organelles
What are the similarities between plant and animal cells?
Both have nucleus, mitochondria, same organelles for the most part, same size, level of complexity, same DNA for the most part
What are the differences between plant and animal cells?
Plant cells have very large vacuoles, chloroplasts and cell walls, whereas animal cells don’t
What are some unique characteristics of archaea?
- they are extremophiles –> can survive extreme conditions
- can survive high temperatures e.g. volcanoes
- older, longer living
What is the structure, function and appearance of a nucleus?
Structure: double membrane, contains DNA
Function: Stores genetic material
Appearance: Big spot in the middle of a cell
What is the structure, function and appearance of ribosomes?
Structure: no membrane, made up of proteins and rRNA
Function: Protein synthesis
Appearance: Little dots (e.g. on the rough ER)
What is the structure, function and appearance of a rough endoplasmic reticulum?
Structure: Lots of ribosomes bound to it, membrane-bound network of cisternae
Function: Processes and modifies proteins
Appearance: Kinda folded up looking, lots of ribosomes
What is the structure, function and appearance of a smooth endoplasmic reticulum?
Structure: Membrane-bound network of cisternae
Function: Synthesises lipids
Appearance: Network of interconnected, tubular structures
What is the structure, function and appearance of a Golgi apparatus?
Structure: membrane-bound stack of cisternae, not connected
Function: processes and packages proteins
Appearance: stack of flattened, membrane enclose sacs called cisternae
What is the structure, function and appearance of lysosomes?
Structure: membrane-bound vesicle that contains digestive enzymes
Function: digests cell waste and foreign material
Appearance: bubble/sack that grabs/consumes things
What is the structure, function and appearance of a mitochondrion?
Structure: powerhouse of the cell, double membrane, lots of folds called cristae to increase SA, contains mitochondrial DNA
Function: cellular respiration, generates ATP (the energy cells use)
Appearance: little bean looking thing with little folds inside
What is the structure, function and appearance of a chloroplast?
Structure: Very similar to mitochondria, double membrane, will also contain DNA
Function: Photosynthesis, creates energy, contains chlorophyll (responsible for green colour)
Appearance: Small, oval or disk-shaped green organelles
What is the structure, function and appearance of vacuoles?
Structure/appearance: Massive sack in the middle of plant cells, animal cells have them but smaller, membrane bound fluid-filled vesicles
Function: stores substances
What is the structure, function and appearance of a cell wall?
Structure/appearance: external structure surrounding the cell membrane
Function: gives plant cells their structure and protection, separates it from external environment
What is the structure, function and appearance of cytoplasm?
Structure: gelatinous liquid that fills the inside of a cell
Function: allows transport, maintains cell shape and structure, protection, storage, host to metabolic processes
Appearance: the liquid in a cell
What are the benefits and limits of light microscopy?
benefits: simple to use, allows live cell imaging, relatively inexpensive
limits: low resolution, specimens must be thin and semi-translucent
How does a light microscope make specimens visible?
A light source shines through the specimen, which must be finely cut and semi-translucent for light to pass through
How does fluorescent microscopy work?
It uses dyes or stains to make different cell structures glow at specific wavelengths of light
What are the benefits and limitations of fluorescent microscopy?
Benefits: highlights specific structures, useful for studying molecular activity, can be combined with electron microscopy
Limits: requires special staining, some dyes can damage cells, fluorescence fades over time
What can and can’t be seen using fluorescent microscopy?
Can: specific proteins, organelles, DNA and cytoskeleton structures when stained
Can’t: unstained structures, overall cell context without labelling
What is a key advantage of electron microscopy over light microscopy?
It provides much higher resolution, allowing for detailed imaging of complex cell structures
How does electron microscopy create images of specimens?
It reflects an electron beam off the specimen and collects data on how electrons interact with it to form an image
What structures can and can’t be seen using electron microscopy?
Can: detailed structures of organelles (e.g. mitochondria, ribosomes, endoplasmic reticulum), cell membrane details
Can’t: live cell movement, colour information, dynamic processes
What is the phospholipid bilayer made of?
Two layers of hydrophilic phosphate heads and hydrophobic fatty acid tails
Why is the phospholipid bilayer important?
It is highly specialised and helps regulate what enters and exits the cell
What are two major types of membrane proteins?
- fibrous proteins
- globular proteins
What is the fluid mosaic model?
it describes the cell membrane as a constantly moving structure made of many small parts that work together
what are some types of transport proteins in the cell membrane?
ion channels, protein pumps, aquaporins and GLUT transporters
Why is the cell membrane important for homeostasis?
It regulates internal and external conditions
What does it mean that the membrane is ‘selectively permeable’?
It only allows certain molecules to pass through while blocking others
Why and where does oxygen move through the cell membrane?
Why: needed for cellular respiration
Where: passes through the lipid bilayers
Why and where does carbon dioxide move through the cell membrane?
Why: waste product of respiration
Where: passes through lipid bilayer of membrane
Why and where does water move through the cell membrane?
Why: moves via osmosis to balance concentration
Where: passes through aquaporins (channel proteins)
Why and where does glucose move through the cell membrane?
Why: needed for energy production
Where: passes through carrier proteins
Why and where do ions move through the cell membrane?
Why: important for nerve signals, muscle function and balance
Where: passes through ion channels or pumps
Why and where do amino acids move through the cell membrane?
Why: needed for protein synthesis
Where: passes through carrier proteins
Why and where do large molecules (e.g. proteins) move through the cell membrane?
Why: used in cell functions
Where: passes through vesicles via endocytosis / exocytosis
Why and where do enzymes move through the cell membrane?
Why: used in digestion, metabolism and cell reactions
Where: passes through vesicles via exocytosis or stays embedded in membrane
Why and where do waste products move through the cell membrane?
Why: must be removed to maintain cell health
Where: passes through vesicles via exocytosis
Why and where do hormones move through the cell membrane?
Why: needed for cell signaling
Where: Passes through lipid bilayer (if non-polar) or via receptors (if polar)
