3 Flashcards
· Cell Theory.
Early: Organisms made of one or more cells, Cell is the fundamental unit of life, Cells come from preexisting cells. Additional: All cells have same basic chemical composition, All cells use energy, All cells contain DNA that is duplicated and passed o
· Why are cells too small to be seen with the naked eye?
Because cells must have abundant surface area to allow the cell to quickly exchange materials with its surroundings.
· List and explain the four features common to all cells.
DNA/RNA, ribosomes, cytoplasm, cell membrane
· What is the difference between the nucleus and a nucleoid?
nucleoid - irregularly shaped region of cytoplasm containing a single, circular DNA molecule. nucleus - membrane bound sac that contains DNA (eukaryotic cell.)
· Study the generalized body plan of a prokaryote – Draw, label and learn the functions of each part.
Split out functions of parts
· List the organelles of Eukaryotic cells
Nucleus, RER, SER, GA, Lysosome, Peroxisome, Mitochondria, chloroplast, central vacuole
· What is endoplasmic reticulum?
An extension of the nuclear envelope that forms a continuous, folded compartment
What is the function of smooth ER?
Membrane network lacking ribsomes, SER makes lipids, detoxifies drugs and poisons.
What is the function of rough ER?
Synthesizes proteins destined for secretion from the cell.
What is a ribosome?
Structure built of RNA and protein where mRNA anchors during protein synthesis. Both free in cytoplasm and bound to rough ER.
Where are the proteins produced by free ribosomes used?
In the cytoplasm
Where are the proteins produced by RER ribosomes used?
In specialized organelles, cell membrane or secreted out of the cell
What is the function of the Golgi apparatus? Pap
- **processes polypeptides and lipids delivered from the ER.
- **adds carbs to proteins and lipids making them glycoproteins and glycolipids.
- **Packages finished products in vesicles that carry them to the plasma membrane or to lysosomes.
What are Lysosomes?
Enzymes in lysosome break down large organic molecules into smaller subunits by hydrolysis releasing them into cytoplasm for the cell to use. Breaks down and recycles cellular debris and captured pathogens.
What is the function of Peroxisomes?
Originate in ER and contain enzymes that break down toxic substances like hydrogen peroxide and fatty acids. Produce cholesterol and othe lipids.
· Describe the structure and function of Mitochondria.
Contains two membranes forming inner (cristae) and outer compartments and a fluid interior (matrix) that contains its own DNA and ribsomes. Function - Makes the energy molecule ATP through aerobic respiration.
Name two important functions of the nucleus in a eukaryotic cell.
Keeps DNA away from potentially damaging reactions in the cytoplasm. Nuclear envelope controls when DNA is accessed and controls the passage of certain molecules across its membrane.
What are the components of the nucleus?
Nuclear envelope, Nucleoplasm, Nucleolus
Nuclear envelope?
2 lipid bilayers pressed together as a single membrane surrounding the nucleus. Outer bilayer continuous with ER. Has nuclear pores to allow certain substances to pass thru membrane.
Nucleoplasm?
Viscous fluid inside nuclear envelope
Nucleolus?
Dense region in the nucleous where subunits of ribosomes are assembled from proteins and RNA
Chromatin?
All DNA and its associated proteins in the nucleus.
Chromosome?
Single DNA molecule with its attached proteins. Visible during cell division. Humans 46.
· What is an endomembrane system?
A series of interacting organelles between the nucleus and the plasma membrane.
What are the major organelles of the endomembrane system?
Nuclear envelope, ER, GA, Lysosomes, Vacuoles, Cell membrane.
What does the Endomembrane system do?
Makes/Modifies/Transports proteins and lipids for secretion or insertion into cell membranes. Destroys toxins, recycles wastes.
What organelles are involved in cellular digestion?
lysosomes, vacuoles, peroxisomes
What is the function of Vacuoles?
contains a watery soln of enzymes that degrade and recycle molecules and organelles. 90% of cell’s volume, turgor pressure helps plants stay upright and rigid.
· What are plastids? List their common types.
involved in the synthesis and storage of food, commonly found within the cells of photosynthetic organisms. Chloroplast, Chromoplast, Leucoplast.
A double membrane bound organelle
· Describe the function of Chloroplast.
Function in storage and photosynthesis in plants and some kinds of algae. Use sunlight to produce food for the cell.
Describe the structure of a chloroplast.
Two outer layers enclose an exzyme rich fluid sac called the stroma. In the stroma is a third membrane system folded into flattened sacs called thylakoids which are stacked and interconnected in structures called grana. Photosynthetic pigments such as chlorophyll are embedded in thylakoids.
· Name the 3 kinds of Cell Junctions in animals and one kind found in plants.
Animal: Tight, Adhering, Gap Plant: Plasmodesmata
· What are cytoskeletons?
Network of protein tracks and tubules which function in structural support, aid cell division, organelle transport and cell movement.
name the different kinds of cytoskeletons found in cells?
Microfiliments, intermediate filaments, microtubules
Tight Junction
Fuses membranes of adjacent animal cells together, forming an impermeable barrier between them. Digestive tract.
Adhering junction
Connects a cell to its neighbor or to extracellular matrix using intermediate filaments. Holds skin cells in place.
Gap junction
Protein channel that links cytoplasm of adjacent animal cells. Heart muscle
Plasmodesmata junction
Channels that connect adjacent cells in plants.
Microfiliments
long rod composed of the protein actin, strength to survive stretching and compression
Intermediate filaments
60 types of protein, maintain cell shape by forming a scaffold in cytoplasm
Microtubules
from protein tubulin, pull chromosomes apart, for tracks for protein
