Summarizing Eukaryotic Cells

Summary of lessons so far

Like a prokaryotic cell, a eukaryotic cell has a plasma membrane, cytoplasm, and ribosomes. However a eukaryotic cell is typically larger than a prokaryotic cell, has a true nucleus (meaning its DNA is surrounded by a membrane), and has other membrane-bound organelles that allow for compartmentalization of functions. The plasma membrane is a phospholipid bilayer embedded with proteins.

The nucleus’s nucleolus is the site of ribosome assembly. Ribosomes are either found in the cytoplasm or attached to the cytoplasmic side of the plasma membrane or endoplasmic reticulum. They perform protein synthesis. Mitochondria participate in cellular respiration; they are responsible for the majority of ATP produced in the cell. Peroxisomes hydrolyze fatty acids, amino acids, and some toxins. Vesicles and vacuoles are storage and transport compartments. In plant cells, vacuoles also help break down macromolecules.

Animal cells also have a centrosome and lysosomes. The centrosome has two bodies perpendicular to each other, the centrioles, and has an unknown purpose in cell division. Lysosomes are the digestive organelles of animal cells.

Plant cells and plant-like cells each have a cell wall, chloroplasts, and a central vacuole. The plant cell wall, whose primary component is cellulose, protects the cell, provides structural support, and gives shape to the cell. Photosynthesis takes place in chloroplasts. The central vacuole can expand without having to produce more cytoplasm.

Glossary of Words

Cell wall

rigid cell covering made of various molecules that protects the cell, provides structural support, and gives shape to the cell

Central vacuole

large plant cell organelle that regulates the cell’s storage compartment, holds water, and plays a significant role in cell growth as the site of macromolecule degradation

Centrosome

region in animal cells made of two centrioles

Chlorophyll

green pigment that captures the light energy that drives the light reactions of photosynthesis

Chloroplast

plant cell organelle that carries out photosynthesis

Chromatin

protein-DNA complex that serves as the building material of chromosomes

Chromosome

structure within the nucleus that is made up of chromatin that contains DNA, the hereditary material

Cytoplasm

entire region between the plasma membrane and the nuclear envelope, consisting of organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals

Cytosol

gel-like material of the cytoplasm in which cell structures are suspended

Eukaryotic cell

cell that has a membrane-bound nucleus and several other membrane-bound compartments or sacs

Lysosome

organelle in an animal cell that functions as the cell’s digestive component; it breaks down proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles

Mitochondria

(singular = mitochondrion) cellular organelles responsible for carrying out cellular respiration, resulting in the production of ATP, the cell’s main energy-carrying molecule

Nuclear envelope

double-membrane structure that constitutes the outermost portion of the nucleus

Nucleolus

darkly staining body within the nucleus that is responsible for assembling the subunits of the ribosomes

Nucleoplasm

semi-solid fluid inside the nucleus that contains the chromatin and nucleolus

Nucleus

cell organelle that houses the cell’s DNA and directs the synthesis of ribosomes and proteins

Organelle

compartment or sac within a cell

Peroxisome

small, round organelle that contains hydrogen peroxide, oxidizes fatty acids and amino acids, and detoxifies many poisons

Plasma membrane

phospholipid bilayer with embedded (integral) or attached (peripheral) proteins, and separates the internal content of the cell from its surrounding environment

Ribosome

cellular structure that carries out protein synthesis

Vacuole

membrane-bound sac, somewhat larger than a vesicle, which functions in cellular storage and transport

Vesicle

small, membrane-bound sac that functions in cellular storage and transport; its membrane is capable of fusing with the plasma membrane and the membranes of the endoplasmic reticulum and Golgi apparatus