A
What structure controls what enters and leaves the cell?
Cell membrane
Where is most of the DNA found in a eukaryotic cell?
Nucleus
What organelle is the main site of aerobic respiration?
Mitochondrion
What structure is responsible for protein synthesis?
Ribosome
What is the smallest unit capable of carrying out life processes?
Cell
What property allows the membrane to regulate which substances cross it?
Selective permeability
What structure inside the nucleus produces ribosomal subunits?
Nucleolus
What are the folds of the inner mitochondrial membrane called?
Cristae
What makes rough ER appear “rough”?
Ribosomes attached to its surface
What structure separates the cytoplasm from the external environment?
Cell membrane
What type of molecule forms the basic structure of the membrane?
Phospholipid
What DNA–protein structure becomes highly condensed during cell division?
Chromosome
Why is the inner mitochondrial membrane highly folded?
To increase surface area for ATP production.
What is the main function of the rough ER?
Synthesis and initial processing of proteins.
What is one advantage of membrane-bound organelles?
They create specialized compartments for different reactions.
A cell is 8 μm long in reality and appears 40 mm long in an image. What is the magnification?
×5,000
A nucleus has an actual diameter of 6 μm. In a diagram, it measures 18 mm. What is the magnification?
×3,000
A mitochondrion appears 24 mm long in an electron micrograph. Its actual length is 4 μm. Calculate the magnification.
×6,000
A structure is 2 μm in reality and appears 10 mm in an image. What is the magnification?
×5,000
A cell image is shown at ×2,500 magnification. The cell measures 12 mm on the image. What is the cell's actual size?
4.8 μm
Why can oxygen cross the membrane without a transport protein?
It is small and non-polar, so it can diffuse through the hydrophobic core.
Why is compartmentalization of DNA inside the nucleus advantageous for eukaryotic cells?
It separates transcription from translation and helps regulate gene expression.
This organelle contains digestive enzymes and can fuse with vesicles containing damaged cell components or unwanted material. Identify the organelle.
Lysosome
A mutation prevents ribosomes from attaching to the ER. Which type of protein production would be most directly affected?
Proteins destined for secretion, membranes, or the endomembrane system.
A cell contains an extensive network of flattened membrane-bound sacs covered with ribosomes. Proteins produced here are transported in vesicles to another organelle for further modification and sorting. Identify the structure and the organelle that receives these vesicles.
Rough endoplasmic reticulum → Golgi apparatus