Part 2 - What Makes Up An Organism Flashcards
What are cells?
They are the basic structural and functional unit of all organisms. Cells may exist as independent units of life or may form colonies (multicellular) or tissue to form plants or animals
Cells are classified into two types. Can you name these?
Prokaryotic cells and eukaryotic cells
Which cell type was thought to be the first life form on earth?
Prokaryotic cells specifically bacteria
What chemicals make up a standard human?
Carbon Nitrogen Water Phosphorus Iron 20 other elements
From what we know when were microscopic organisms/ cells first discovered? And who discovered them?
1964
By a Dutch man named Antoni van Leeuwenhoek
How long have microscopes been around?
1600’s
What enabled van Leeuwenhoek to see animalcules?
He designed and made his own lenses by curving them (more than anybody else could) which magnified up to 500 times the actual size
What did van Leeuwenhoek discover?
Van Leeuwenhoek discovered ‘animalcules’ small single celled organisms that live in water, known today as Protists. At the time however he didn’t recognise them as such - he thought they were miniature versions of the animals we see day to day
From what observations did Robert hook define cells?
Observation of self contained units in cork led to Hooke defining cells
Why could Hooke initially not see the animalcules that van Leeuwenhoek observed and described?
His microscope was not powerful, but he was able to observe animalcules he managed to increase magnification
What pioneering discovery made by Robert brown in 1830?
He discovered that cells he observed contained a nucleus
Apart from cell theory what else did Robert brown discover?
Brownian motion - the movement of particles within pollen grains
What did the scientists Schwann and schleiden discover?
They both discovered that both plants and animals are made up of a cell and that these cells contain and nucleus.
What breakthrough in cell biology did the scientist Remak make?
That all cells make cells. The divide in to two and replicate. Essentially this was the start of embryology I.e the fact that a sperm cell and an egg cell fuse to form a single cell. The single cell then divides in to two cells then these two cells divide in to 4 cells and so on.
What is the outer boundary of a cell called?
The cell membrane
What is the main function of the cell membrane?
It’s main function is to keep the cell contents separate from the external environment and at a fairly constant concentration
It also restricts the movement of molecules from inside the cell to the outside and vice versa, so effectively acting as a barrier
What is the concentration of a liquid defined as?
The concentration of a liquid is defined as the number of particles within a particular volume
What is the gelatinous of jelly like liquid inside of a cell called?
Cytosol or cytoplasm
Why does the vicious internal environment of a cell need to be maintained?
To allow metabolism (the chemical processes) within the cell to occur
Define the term metabolism?
All the chemical processes by which cells produce the energy and substances necessary for life. Food is separated into the parts it is made up of to produce heat and energy and to help with growth of the cell.
Where are organic molecules found?
Naturally found in all living organisms and systems
What are organic molecules composed of?
Carbon atoms in long chains or rings with other atoms such as oxygen, hydrogen and nitrogen attached
What are cell membranes primarily made up of?
Phospholipids
What type of molecules are phospholipids?
Organic molecules
Define the term phospholipids?
An organic compound that compose of fatty acids (lipids) and phosphates, it makes up a cell membrane
What does hydrophobic mean?
Water hating
What does hydrophilic mean?
Water loving
How many parts of phospholipids composed of in a cell membrane?
2 parts
Lipids (fatty acids)
Phosphates (phosphoric acid)
Which part of the phospholipid cell membrane is hydrophobic?
The lipids - fatty organic molecules
Which part of the phospholipid cell membrane is hydrophilic?
The phosphate groups
Why do the lipid in a phospholipids associate together?
Because of their non polar properties, which means that they group together away from the water polar molecules
What is a bilayer?
It is a film of membrane with two molecular layers
What is the function of a pore cross membrane in a cell?
To allow transport of the substances in and out of the cell
It is selectively permeable and only allows certain substances through
Define the term permeable?
Allows substances to pass or diffuse through
What is the difference between Brownian motion and diffusion?
Both Brownian motion and diffusion are processes involving the movement of molecules. Brownian motion is the random movement of molecules whereas diffusion is the movement o molecules down a concentration gradient from an area of high concentration to an area of low concentration
What does an animal cell usually consist of?
Nucleus Cytoplasm Mitochondria Lysosome Free ribosomes Smooth endoplasmic reticulum Rough endoplasmic reticulum
What is a nuclear envelope in a cell?
It is a double phospholipid membrane that surrounds the nucleus
What does the nucleus of a cell contain?
Deoxyribonucleic acid DNA
What is the rough endoplasmic reticulum of an animal cell studded with?
Ribosomes
What are plants cells surrounded by which is a rigid barrier outside the cell membrane?
Cell wall
What is a vacuole and which kingdom cell is it usually present in?
Plant cell
It is a large central vacuole, a water filled space enclosed by a membrane
Which kingdom cells are chloroplasts found in?
Plant cells
What do chloroplasts contain and why?
Chlorophyll
It is a green coloured pigment used in photosynthesis
What does a plant cell usually consist of?
7
Chloroplast Smooth endoplasmic reticulum Nucleus Rough endoplasmic reticulum Free ribosomes Mitochondria Vacuole
What is the most prominent and generally the largest feature of a eukaryotic cell?
The nucleus
In a cell, What has two membranes, the inner membrane is convoluted or wiggly in shape and provides all the energy the cell needs to function?
Mitochondria
In a cell which organelle is the transport system?
Endoplasmic reticulum
In a cell what is the part of endoplasmic reticulum furthest from the nucleus, smooth in appearance?
Smooth endoplasmic reticulum
In a cell what is granular in appearance due to ribosome attached to it?
Rough endoplasmic reticulum
In most cells a nucleus can be observed, what is the main constituent of a nucleus?
The nucleus contains the hereditary material deoxyribonucleic acid usually known as DNA, which is packaged into chromosomes
Do prokaryotic cells have organelles?
No
What happens to cells that is the reason why all living things grow?
All living things grow by multiplying their cells in the process of cell division
