Biology: Chapter 4 - Pictures Flashcards
What is this?
What is it’s significance?
Surface to Volume Ratio
As a cell gets larger, its volume increases at a faster rate than its surface area. If the cell radius increases by 10 times, the surface area increases by 100 times, but the volume increases by 1,000 times. A cell’s surface area must be large enough to meet the needs of its volume.
Which type of cell is this?
Label the parts.
What is its significance?
Prokaryotic Cell
Prokaryotic cells lack internal compartments. Not all prokaryotic cells have a flagellum or a capsule like the one illustrated here, but all have a nucleoid region, ribosomes, a plasma membrane, cytoplasm, and a cell wall.
What type of cell is this?
Label the cell.
What is its significance?
Animal Cell
In this generalized diagram of an animal cell, the plasma membrane encases the cell, which contains the cytoskeleton and various cell organelles and interior structures suspended in a semifluid matrix called the cytoplasm. Some kinds of animal cells possess fingerlike projections called microvilli. Other types of eukaryotic cells, for example many protist cells, may possess flagella, which aid in movement, or cilia, which can have many different functions.
What type of cell is this?
Label the parts of the cell.
What is its significance?
Plant Cell
Most mature plant cells contain large central vacuoles that occupy a major portion of the internal volume of the cell and organelles called chloroplasts, within which photosynthesis takes place. The cells of plants, fungi, and some protists have cell walls, although the composition of the walls varies among the groups. Plant cells have cytoplasmic connections through openings in the cell wall called plasmodesmata. Flagella occur in sperm of a few plant species, but are otherwise absent in plant and fungal cells. Centrioles are also absent in plant and fungal cells.
What is this?
Label the parts.
The Nucleus
The nucleus is composed of a double membrane, called a nuclear envelope, enclosing a fluid-filled interior containing the chromosomes. In cross section, the individual nuclear pores are seen to extend through the two membrane layers of the envelope. The pore is lined with protein, which acts to control access through the pore.
What is this?
Label the parts.
Mitochondria
The mitochondria of a cell are sausage-shaped organelles within which oxidative metabolism takes place, and energy is extracted from food using oxygen. (a) A mitochondrion has a double membrane. The inner membrane is shaped into folds called cristae. The space within the cristae is called the matrix. The cristae greatly increase the surface area for oxidative metabolism. (b) Micrograph of two mitochondria, one in cross section, the other cut lengthwise.
What is this?
Label the parts.
Chloroplast.
Bacteria-like organelles called chloroplasts are the sites of photosynthesis in photosynthetic eukaryotes. Like mitochondria, they have a complex system of internal membranes on which chemical reactions take place. The internal membranes of a chloroplast are fused to form stacks of closed vesicles called thylakoids. Photosynthesis occurs within these thylakoids. Thylakoids are stacked one on top of the other in columns called grana. The interior of the chloroplast is bathed in a semiliquid substance called the stroma.
What is this?
What is significant about it?
Endosymbiosis.
What is this?
What is significant about it?
Centrioles
What is this?
What is significant about it?
The central vacuole of a plant cell.
A plant’s central vacuole stores dissolved substances and can increase in size to increase the surface area of a plant cell.
What is this?
What is significant about it?
A Central Vacuole in a Paramecium.
The contractile vacuole in Paramecium collects and eliminates excess water in the cell. Once filled, the contractile vacuole contracts and expels the water through a pore.
What is this?
What is it’s significance?
Flagellum.
(a) A eukaryotic flagellum springs directly from a basal body and is composed of a ring of nine pairs of microtubules with two microtubules in its core. (b) Human sperm cells have one flagellum.
What is this?
What is its significance?
Molecular Motor
Vesicles that are transported within cells are attached with connector molecules, such as the dynactin complex shown here, to motor molecules, like dynein, which move along microtubules.
What is this?
What is it’s significance?
A plant cell wall.
Plant cell walls are thick, strong, and rigid. Primary cell walls are laid down when the cell is young. Thicker secondary cell walls may be added later when the cell is fully grown. The middle lamella lies between the walls of adjacent cells and glues the cells together.
What is this?
What is the significance of this?
The Extracellular Matrix.
Animal cells are surrounded by an extracellular matrix (ECM) composed of various glycoproteins. The ECM carries out a variety of functions that influence cell behavior, including cell migration, gene expression, and the coordination of signaling between cells
What is this?
What is it’s significance?
Label.
How Solutes Create Osmotic Pressure.
A cell is an enclosed structure, and so as water enters the cell from a hypotonic solution, pressure is applied to the plasma membrane until the cell ruptures. This hydrostatic pressure is counterbalanced by osmotic pressure, the force required to stop the flow of water into the cell. Plant cells have strong cell walls that can apply adequate osmotic pressure to keep the cell from rupturing.
What is this?
What is its significance?
Endocytosis.
Endocytosis is the process of engulfing material by folding the plasma membrane around it, forming a vesicle. (a) When the material is an organism or some other relatively large fragment of organic matter, the process is called phagocytosis. (b) When the material is a liquid, the process is called pinocytosis.
What is this?
What is its significance?
Phagocytosis
Endocytosis is the process of engulfing material by folding the plasma membrane around it, forming a vesicle. (a) When the material is an organism or some other relatively large fragment of organic matter, the process is called phagocytosis.
What is this?
What is its significance?
Pinocytosis
Endocytosis is the process of engulfing material by folding the plasma membrane around it, forming a vesicle. When the material is a liquid, the process is called pinocytosis.
What is this?
What is its significance?
Exocytosis.
Exocytosis is the discharge of material from vesicles at the cell surface. (a) Proteins and other molecules are secreted from cells in small pockets called secretory vesicles, whose membranes fuse with the plasma membrane, thereby allowing the secretory vesicles to release their contents to the cell surface. (b) In the photomicrograph, you can see exocytosis taking place explosively.
What is this?
What is it’s significance?
Receptor Mediated Endocytosis.
Cells that undergo receptor-mediated endocytosis have pits coated with the protein clathrin that initiate endocytosis when target molecules bind to receptor proteins in the plasma membrane. In the photomicrographs, a coated pit appears in the plasma membrane of a developing egg cell, covered with a layer of proteins (80,000x). When an appropriate collection of molecules gathers in the coated pit, the pit deepens, and eventually seals off to form a vesicle.
What is this?
Label.
What is its significance?
The Plasma Membrane.
Plasma membranes are made up of phospholipid bilayers.
All plasma membranes have the same basic structure or phospholipids and proteins called the fluid mosaic model.
