The Cell Flashcards
What are cells
The structural and functional units of an organism
The smallest structure capable of performing all functions necessary to life
What terms describe the amount of cells an organism has
Unicellular - one cell
Multicellular - at least 2 cells, can be many many more
What are the three types of cell in nature
Prokaryotic : lack a membrane enclosed nucleus. Simple bacteria
Eukaryotic: have a membrane bound nucleus, and organelles. Protists, fungi, plants, animals
Archaeans: posses qualities of both, archaebacteria
What are the three statements of cell theory
- all organisms are made of cells
- cells are the basic living unit for all life
- cells come from previous cells
How big are cells
Small
Less than 1 mm
Some as small as 1 um (1/1000 mm)
Why do cells need to be small
Cells consume food and produce waste, this is relative to cell volume
Cells thus need to take in food and let out waste, this is relative to cell surface area
As a cell becomes bigger the volume increases at a faster rate than surface area
At a certain size the cell would not be able to take in enough food to feed it fast enough, and let out enough waste fast enough
What might cells do to increase surface area
The outer membrane might fold and wrinkle to increase surface area without increasing volume
What are the main cells we learn about
Eukaryotic cells, they have a nucleus and organelles. And form the base of animals, plants, fungi, and protists
What is the cell membrane
A phospholipid bi-layer that is embedded with protein molecules,
Surround the cell and separates the inside of the cell from the out
What fills the inside of the cell
A semi fluid medium called cytoplasm,
Composed of water, salts, and dissolved organic molecules
What are cell walls
A permeable but protective wall that is around the cell membrane, gives rigidity and protection to certain cells
What types of cell have cell walls
Plants cells have 1 cellulose and 1 lignin cell wall
Fungi have cellulose and chitin cell walls
Some algae have cellulose cell walls
What are organelles
Well defined sub cellular structures that perform a specific, important function for the cell
What is the nucleus
A prominent organelle with a diameter of ~5um
Stores the genetic information of the cell, DNA, and controls cell functions
What is inside the nucleus
Chromatin: DNA + Proteins, condenses into chromosomes
What is the semi fluid inside the nucleus
Nucleoplasm
What is the nucleolus
The area where ribosomal RNA (rRNA) is produced
What is around the nucleus
The nuclear envelope
What is attached to the nuclear envelope
The rough ER
What are nuclear pores
Holes around 100nm that permit bidirectional transport of proteins and ribosome subunits
What do ribosomes do
Synthesis proteins using mRNA as a template
What are ribosomes made of
Small + large subunits, each is a complex of unique ribosomal RNA and proteins
Where are ribosomes found
In the cytoplasm, groups called polyribosomes, and RER
What organelles are in the endomembrane system
Nuclear envelope + ER + golgi + vesicles
Does transport and processing of the cell
What is the Endoplasmic Reticulum
Complicated system of membranous channels and sacs (flattened vesicles)
Connects to nuclear envelope
What is the rough ER
Studded with ribosomes which synthesis proteins
Inside the RER proteins are processed and modified
What is the smooth ER
Connected to rough ER, has no ribosomes
Synthesizes phospholipids, producers testosterone, detoxifies drugs, stores calcium ions
Forms vesicles which transport materials to golgi
What is the Golgi apparatus
3-20 slightly curved sacs, stacked on top of each other
One side faces nucleus, other faces membrane
What does the Golgi apparatus do
Receives proteins + lipid vesicles from ER, as they move through they are modified, repackaged into secretory vesicles
Forms lysosomes
What is secretion
Secretory vesicles move from Golgi and release materials outside cell