HUMAN BIO y11 Flashcards
What is the cell theory?
The cell theory states that all organisms are made of cells, which are the basic unit of life and arise from
pre-existing cells.
What is the cell membrane?
cell membrane – the outer boundary of the cell
What is the cytoplasm?
those parts of the cell within the cell membrane, except for the nucleus; includes the
jelly-like fluid and the organelles suspended in it
organelles
structures suspended in the cytoplasm that carry out particular functions
cytosol
the liquid part of the cytoplasm
cytoskeleton
internal scaffolding of protein fibres within the cytoplasm
inclusions
chemical substances occurring as granules or liquid droplets in the cytoplasm.
What are Lyosomes
Lysosomes are small spheres, bound by a membrane, that are formed from the Golgi body.
What is the cytoplasm?
Cytoplasm is the jelly-like or watery material inside the cell that fills all the space between the nucleus and the cell membrane. It is made up of the cytosol and organelles
What are ribosomes?
Ribosomes are very small, spherical organelles. At the ribosomes, amino acids are joined together to make proteins. Ribosomes may be either free in the cytoplasm or attached to membranes within the cells such as endoplasmic reticulum.
Endoplasmic reticulum?
The network of channels formed by the parallel membranes is called the endoplasmic reticulum.
What can the endoplasmic reticulum be classified into?
Rough endoplasmic reticulum
Smooth endoplasmic reticulum.
What is the golgi body?
The Golgi body is a series of flattened membranes stacked one upon the other.
What are lyosomes?
Lyosomes are small spheres, bound by a membrane, that are formed from the golgi body.
What is the mitochondria?
Chemical reactions of cellular respiration occur in the mitochondria. It provides energy for the cell.
What are the cilia and flagella?
If the projections are short and numerous, resembling tiny hairs, they are called cilia. If they are longer and there is only one or two of them, they are called flagella.
What is they Cytoskeleton?
The cytoskeleton is a framework of protein fibres that gives the cell its shape and assists cell movement.
What does the cytoskeleton consist of?
Microtubules - hollow rods that keep organelles in place or move them around the cell.
Microfilaments - Which move materials around the cytoplasm or move the whole cell.
What is homeostasis?
Body systems work together to ensure that the cellular environment is kept constant. This is called homeostasis.
What is the main structure of the cell membrane?
The main structure of the membrane is composed of phospholipid molecules, which are lipid molecules containing a phosphate group
What is the currently accepted model for cell membrane structure
fluid mosaic model
What is the main structure of the membrane composed of?
Phospholipid molecules
What are phospholipid molecules?
They are lipid molecules containing a phosphate group.
What is the bilayer?
The phospholipids are arranged in two layers called the bilayer.
Is the phospholipid head hydrophilic or hydrophobic?
Hydrophilic
Is the phospholipid tail hydrophilic or hydrophobic
Hydrophobic
Define Extracellular fluid?
The extracellular fluid is the fluid that surrounds the outside of the cell.
Name three organelles commonly found in human cells.
Nucleus, Mitochondria, Golgi bodies, Rough Endoplasmic Reticulum, Smooth Endoplasmic reticulum, Centrioles, Lyosomes, Ribosomes
Describe the function of the mitochondria
The site where some of the chemical reactions of cellular respiration occur, making energy available to the cell.
Describe the function of the Endoplasmic Reticulum
Membranes that provide a surface for chemical reactions and form channels for transporting or storing substances.
What is the function of Ribosomes?
The sites where amino acids are joined to make proteins.
What is the function of the nucleus.
Contains DNA that determines the type of proteins a cell can make
What is a vesicle?
Vesicles are bubbles of liquid in the cytoplasm. The bubble is surrounded by a membrane.
What are two ways vesicles can be formed?
Some vesicles are formed at the edges of the membranes of the golgi bodies; others are formed when particles or liquids are taken into the cell.
Many cells have inclusions. Give two examples of inclusions.
The haemoglobin in red blood cells; The pigment melanin, which is found in the pigmented cells in the skin, hair and iris of the eye
What are two substances that are required by all cells
Oxygen and glucose
Name two substances that have to be removed from all cells
Carbon dioxide, water and waster other than CO2
Define active transport
The use of energy to transport more substances, usually ions, across a cell membrane. For example: sodium-potassium pump
What is the difference between the cytosol and cytoplasm
Cytoplasm is the thick fluid inside the cell membrane and all the structures that are suspended in the fluid, while the cytosol is the liquid part of they cytoplasm
The nuclear membrane has large gaps in it. Explain the importance of these gaps
The nuclear pores allow large molecules to pass through the nuclear membrane.
Why are most cells microscopic
it gives them a large surface are in relation to their volume. So they are able to exchange materials efficiently
Explain the role of proteins in transport across a cell membrane
Carrier proteins are required to move water-soluble and large molecules into and out of the cell. Channel proteins are required to move water, and small ions that are not lipid souble, either side of the membrane.
Unlike plant cells, animal cells have no cell wall. How is this shape of a human cell maintained?
Human cells have a framework of protein fibres in the form of microfilaments and microtubules. These maintain the shape of the cell.
What is osmosis?
Osmosis is a special type of diffusion, the diffusion of a solvent, usually water. Osmosis requires a cell membrane, whereas diffusion does not require a cell membrane.
