2.1 + 2.2 Flashcards
WHat are living things made up of
Cells
What was cell theory developed in conjunction with
Discovery of Cells
What are the four main components of cell theory
-Cells are the structural unit of all living things
- cells are the functional unit of life, carrying out all the living processes
- Every cell arise froma pre-existing cells
- Cells contain hereditary material
What are criteria to classify something as living
- are complex and have an organised structure
- take in energy from their surroundings and use it
- maintain a composition that is chemically different from their external environment
- respond to stimulis
- are able to reproduce
- grow and respond
What is something that all cells have
A membrane which encloses the cell, the cytoplasm which consists of mainly water and also a small number of structures called organelles
Compare compositon of prokaryotic cell as compared to a eukaryotic cell
Prokaryote = non membrane bound organelles, less complex, little internal organisation, smaler, circular DNA, no nucleus, unicellular
Eukaryote = membrane bound organelles, more complex, larger, complex organisation, two or more chromosomes, uni or multicellular
The cell membrane is responsible for ….
controlling what enters and exits a cell
WHat is the cell membrane comprimised of
a phospholipi bilayer
WHat is the role of the cell membrane
Seperates the contents of the cell from the external environment
regulate the passage of substances into and out of the cell
enables cells to recognise one another and to recognise certain substances, such as hormones
enable attachment of the cytoskeleton
How can the structure of the cell membrane be explained and why
A fluid mosaic model as it is islands of protein floating in a sea of lipids.
This term suggests that it’s fluid nature means that it is a dynamic living structure, rather than a static
The term mosaic encompasses the idea that the structure is made up of many components
What are common features found in both prokaryotes and eukaryotes
Both have a phospholipid bi layer cell membrane, ribosomes, chromosomes containign DNA and similar protein synthesis mechanisms
What does similarities in protein synthesis mechanisms betwene prokaryotes and eukarytoes suggest
Common evolutionary past
What does the nucleus control
All cell activities, as it determines which proteins are to be made via protein synthesis and therefor determines the structure and function (enzymes) of the cells
Describe the composition of the nuclues
Contained by a double membrane called the nuclear envelope, which contains nuclear pores that allow substances such as mRNA to leave the nucleus.
Within the nucleus is one or more nuclei which is where RNA is synthesised
What is the role of the mitochondria
Are where the latter stages of aerobic respiration occurs
What type of cells require higher numbers of mitochondria
Cells such as muscle cells and sperm cells require a larger number of mitochondria.
Describe the composition of the mitochondria
Double membrane. The inner membrane is folded forming a structure called cristae which increases surface area, allowing for efficient synthesis of ATP energy
Describe the role of chloroplasts
Double membraane bound organelle involved in the synthesis and storage of food and is commonly found within the cells of photosynthetic organisms like plants
Describe the compositon of chloroplasts
Double membrane. Within the membrane are flattened membrane sacs called thykaloids which contain the chemical chlorophyll. These thykaloids are stacked into columnns called grana. The fluid that surrounds them is called stroma
Describe the function of vacuoles
They are used in the control of water and salt balance. Plant cells have large vacuoles, helping to maintain the cell’s structure and shape. Some unicellular fresh-water organisms have contractile vacuoles which are able to remoe excess water that enters the cell. SOme cells use vacuoles to store waste products.
Describe the structure of vacuoles
Fluid filled spaces surrounded by a membrane. They can contain solutes such as salts, sugars and amino acids.
What is a small vacuole called and what are they used for
Vesicles and are used in endo and exocytosis. Specialised vesicles called lysosomes contain digestive enzymes
Describe the function of the golgi apparatus
They are involved in the packaging and secretion of proteins and carbohydrates made by the cell.
What’s an example of a type of cell that has a large number of golgi bodies
Salivary glands as they help to package adn secrete salivary amylase
Describe the structure of th golgi body
Stacks of flattened smooth membrane saces
Describe the function of the endoplasmic reticulum
System of tubules that run from the nuclear envelope to the cell membrane. It helps to transport materials throughout the cell
What is the difference between the smooth and rough endoplasmic reticulums
Rough ER has attached ribosomes - it iws where protein and membrane synthesis occurs. Smooth ER is involved in the synthesis of lipids and the metabolism of carbohydrates
Describe the structure of ribosomes
Made up of two sub-units which are comprised of RNA and protein. Ribosomal protein is produced in the nucleolus. They are non-membrane bound. Found in both pro and eu karyotes
WHat is the function of the ribosomes
Site of translation in protein synthesis
What is the function of lysosomes
Specialised vesicles containing digestive enzymes to help breakdown and digest materials and invaders in the cell
What is the role of the cytoskeleton
Giving cells their shape
Being involed in cell movement (spindle apparatus moves chromosomes)
Holds organelles in place
Provides strnegth to the cell
What are the three main components of the cytoskeleton
Micro-filaments (actin), microtubules (tubin) and intermediate filaments
What is the role of the micro-filaments
Used in cell movement such as chloroplast orientation, pinching of the cell to form daughter cells, formation fo food vacuoles (phagocytosis)
What is the role of the micro-tubules
Allows the movement of the flagella and cilia. Also used in cells to hold organelles in places (e.g. move chloroplasts to the sunny side of the leaf)
What is the role of the intermediate filament
Provide strength for cells, especially in cells prone to wear and tear such as skin cells
Give some examples of the role the cytoskeleton plays in specific cells
Red-blood cell - bi-concave shape increases SA:V ratio
Nerve cell - long axon
Specialised surfaces - mircovili
