Biology: Topic 1: Cell Biology Flashcards
What are living organisms composed of?
Composed of cells.
Outline cell theory (3 points).
1) Cells are the basic unit of life.
2) New cells are formed from pre-existing cells.
3) Cell and cell products make up all structures in living cells.
What are the 7 functions of life?
Metabolism Respiration Sensitivity Homeostasis Growth Reproduction Excretion Nutrition
What are common features of cells? 4 points.
- Surrounded by a membrane.
- Contain genetic material.
- Chemical reactions occurring (catalyzed by enzymes)
- Have their own energy release system for power.
Why can’t the cell theory be proven true?
It would require us to examine every single cell which is impossible.
How can cell theory be proven false?
If someone were to find a discovery that violates the existing cell theory.
What 3 cells fit the cell theory even though they disapprove cell theory?
- Skeletal Muscle.
- Giant Algae.
- Multi Nucleated fungi cell.
What are unicellular cells?
- Also known as single-celled organisms.
- Organisms that consists of one cell only.
Definition of metabolism?
The chemical reactions that occur in a cell, including cell respiration to release energy.
Definition of Hydrolysis?
Break down of Water
How do you calculate magnification?
M = I/A
Are cell walls found in animal or plant cells?
Plant cells only.
How many functions of life do unicellular cells carry.
All 7; Metabolism, respiration, sensitivity, homeostasis, growth, reproduction, excretion, nutrition.
What are functions of life?
They are things that all organisms must do to stay alive.
What are chemical reactions in the cell known as?
Metabolism.
What are the rate of chemical reactions in the cell proportional to?
The volume.
What happens if the ratio of the cell is too small?
1) Substances will not enter the cell as quickly as they are required and waste products will gather together (Accumulate) because they are produced more rapidly.
2) Cells may overheat because the metabolism produces heat faster than it is lost over the cell’s surface.
What is cell differentiation?
The process by which a cell becomes specialized in order to perform a specific function.
How does cell differentiation work?
Differentiation is the process during development whereby newly formed cells become more specialised and distinct from one another as they mature.
What are 3 uses of stem cells?
- Embryonic stem cells.
- Cord blood stem cells.
- Adults stem cells.
What are embryonic stem cells used for?
… embryonic stem cells can be guided into becoming any type of cell that can be used to repair and regenerate diseased of damaged tissues in people.
How are stem cells used to treat Stargardt’s syndrome?
Stem cells replace the photo receptors.
How are stem cells used to treat leukemia?
Stem cells help stimulate new bone marrow growth and restore the immune system.
What is a cell?
- Smallest unit of life.
- The cell is the basic structural, functional, and biological unit of all known living organisms.
Are prokaryotic cells unicellular or multicellular?
Unicellular.
What do human check cells consist of? (Structure)
- plasma membrane
- cytoplasm
- nucleus
- mitochondria
What do moss leaf cells consist of? (Structure)
- cell wall
- plasma membrane
- cytoplasm
- chloroplasts
- sap in vacuole
- nucleus
- vacuole membrane
Why does skeletal muscle not fit the cell theory?
- made up of muscle fibres which are enclosed in a membrane (fits)
- but they are much larger than most cells - 300mm+ (doesn’t fit)
- and they contain hundreds of nuclei (doesn’t fit)
Why does giant algae not fit the cell theory?
- can grow to 100mm but are not multicellular (doesn’t fit) since they only contain one nucleus, rather than hundreds of nuclei
Why does aseptate fungi not fit the cell theory?
- consists of thread like structures called hyphae
- hyphae not divided up into subunits by plasma membrane
- but consist of long undivided sections which contain many nuclei (doesn’t fit)
How many cells in a unicellular organism?
- One
Give two examples of unicellular organisms.
- Paramecium
2. Chlamydomonas
What happens to a cells surface area to volume ratio as it grows larger?
- The SA:V decreases
What does the surface area of a cell determine?
- The rate at which materials enter/leave the cell
What does the volume of a cell determine?
- the rate at which materials are used or produced
What happens if a cell becomes too large?
- it may not be able to take in essential materials or excrete waste substances quickly enough
Why are large organisms multicellular?
Understand why. 1. SA:V decreases as a cell increases 2. if a cell becomes too large, it may not be able to take in essential materials or excrete waste substances quickly enough 3. the cell can no longer survive at this size, so it divides 4. large organisms therefore consist of many cells (multicellular)
Name two advantages of being a multicellular organism.
- cells can take in/excrete essential materials/ waste substances fast enough 2. multicellular allows division of labour, which means different groups of cells can become specialised for different processes
Through what process does a cell become specialised?
- the process of differentiation
What do emergent properties arise from?
- the interaction of the component parts of a complex structure
Define genome.
- an organisms entire set of genes
In multicellular organisms, 100% of the genome is in each cell. Why is this significant?
- each cell has the instructions to develop into any type of cell
Define stem cells. What are their two key qualities?
- cells that have the capacity to divide and differentiate along different pathways - Self renewal: They can continuously divide and replicate - Potency: They have the capacity to differentiate into specialised cell types
Where are adult stem cells found?
- most human tissues including: skin, liver and bone marrow
Give two examples of diseases that can be treated with stem cells.
- Stargadt’s muscular dystrophy (embryonic stem cells) 2. Leukemia (adult stem cells)
What is Stargadt’s muscular dystrophy?
- a genetic disease causing loss of vision
What sort of disease is leukemia? What happens when a person has leukemia?
- cancer 2. abnormally large numbers of white blood cells are produced in the bone marrow
How is leukemia treated?
- adult stem cells used 2. large needle inserted into a large bone, usually the pelvis and fluid is removed from the bone marrow 3. stem cells are extracted from this fluid and are stored by freezing them. They are adult stem cells so only have potential to produce blood cells 4. high dose of chemotherapy drugs to kill all cancer cells in bone marrow. Bone marrow loses its ability to produce blood cells. 5. Stem cell then returned to patient’s body. The cells re-establish themselves in the bone marrow, multiply and start to produce red and white blood cells. 6. In many cases this procedure cures leukemia completely.
How is Stargadt’s muscular dystrophy being treated using stem cells?
researchers have developed methods for making…. 1. embryonic stem cells develop into retina cells (remember that embryonic stem cells can differentiate along any pathway)
Define resolution.
- is the ability of the microscope to show two close objects separately in the image
What does resolution depend on?
- the wavelength of the rays used to form the image 2. the shorter the wavelength, the higher the resolution
Cells are divided into two types. Based on what? What are the two types?
- based on structure 2. prokaryotic and eukaryotic
Cells are divided into two types based on their structure. Compare the two structures. (How are they different)
- eukaryotic cells are divided up by membranes into separate compartments such as the nucleus and mitochondria 2. whereas prokaryotic cells are not compartmentalized.
Do mitochondria have a nucleus?
- NO 2. they have a nucleoid region - it is not bound by a membrane therefore it is not a nucleus
What can surface area to volume ratio help to explain?
- why cells divide 2. many other phenomena kind of a useless card but could be something to consider if they ask you to explain “why cells divide” or ‘some other phenomena’.
Name the process prokaryotic cells undergo to divide.
- binary fission (meaning splitting in two)
What can you observe in a eukaryotic cell using a light microscope? How about an electron microscope?
- light: cytoplasm enclosed in plasma membrane 2. electron: ultrastructure is visible
Name all the organelles in a eukaryotic cell.
Organelle with single membrane: 1. rough endoplasmic reticulum 2. smooth endoplasmic reticulum 3. lysosome 4. Golgi apparatus; vesicles and vacuoles Organelle with double membrane: 5. nucleus 6. mitochondrion 7. chloroplast
What is the role of the lysosome?
- site of hydrolysis / digestion / breakdown of macromolecules
What is the Golgi apparatus?
- an assembly of vesicles and folded membranes involved in the sorting, storing and modification of secretory products
Give similarities of prokaryotic and eukaryotic cells.
- both have a cell membrane 2. both contain ribosomes 3. both have DNA and cytoplasm
Give differences between prokaryotic and eukaryotic cells.
- size - eukaryotic bigger
- ribosomes - eukaryotic bigger
- reproduction - eukaryotic can reproduce sexually as well as asexually
- membrane-bound organelles - eukaryotes have them
- DNA (4 things, found in first chapter of genetics)
State 2 models of membrane structure? Which one superseded the other (and is therefore the one we use today)?
- Davson-Danielli Model
2. Singer-Nicolson Model Singer-Nicolson superseded Davson-Danielli and is therefore the one we use today.