Cell structure & function Flashcards
(23 cards)
What are the hydrophobic parts of phospholipids?
Lipids and proteins; interior part
What are the hydrophilic parts of phospholipids?
The phosphate groups which are in contact with aqueous solution.
Where in the nucleus are ribosomes made?
The nucleolus; the site of rRNA which is what ribosomes are made of.
How does the nucleus direct protein synthesis?
By synthesizing messenger RNA (mRNA) to transport to ribosomes where they can translate message into proteins.
What does the endomembrane system consist of?
Nuclear envelope
endoplasmic reticulum
Golgi apparatus
vesicles
lysosomes
vacuoles
plasma membrane
What is the ER and its two types?
An extensive membrane network continuous with the nuclear envelope;
Smooth ER
(no ribosomes)
Rough ER
(with ribosomes)
Functions of smooth ER?
Lipid synthesis, carbohydrate metabolism, detoxification,
Ca²⁺ storage.
Functions of rough ER?
Synthesizes, folds, and secretes proteins.
What is the role of the Golgi apparatus?
Modifies, stores, and ships proteins from the ER.
Describe the structure of the Golgi apparatus.
Flattened membranous sacs with distinct cis (receiving) and trans (shipping) faces.
Functions of the central vacuole in plants?
Stores inorganic ions,
Supports cell growth and development.
Can occupy up to 90% of cell volume.
What is the function of mitochondria?
Site of cellular respiration; generates ATP from food.
Describe mitochondrial structure.
Double membrane; outer is smooth, inner is highly folded for ATP production.
Chloroplast structure?
Double membrane + internal thylakoid membranes containing chlorophyll.
What is the endosymbiont theory in relation to the mitochondrion?
A free-living aerobic prokaryote was engulfed by a host cell.
The prokaryote evolved into the mitochondrion inside the host.
What is the endosymbiont theory in relation to the chloroplast?
A eukaryotic cell containing mitochondria engulfed a free-living photosynthetic prokaryote.
The prokaryote evolved into the chloroplast organelle inside the host.
Composition of plant cell walls?
Cellulose as a primary wall,
Middle lamella (pectin), Sometimes a secondary wall (in mature cells).
What is the typical size range of cells?
1–100 µm.
Three key parameters in microscopy?
Magnification, resolution (clarity) and contrast.
Types of light microscopy?
Brightfield, stained brightfield, phase contrast, fluorescence.
Resolution limit of light microscopy?
~0.2 µm (200 nm).
Types of electron microscopy?
Scanning Electron Microscopy
(SEM): gives a 3D image
Transmission Electron
Microscopy (TEM): profiles a thin
section of a specimen
Resolution of electron microscopy?
Down to ~2 nm.
