2:Foundations in Biology Flashcards
What is the structure of ribosomes?
- tiny organelles
- 2 sub units
What is the function of ribosomes?
To move along the m-RNA molecules and read the nucleotide code to produce proteins
What is the structure of Golgi apparatus?
- Stack of membrane bound flattened sacs
What is the function of Golgi apparatus?
- lysosome formation
- used in secretion (exocytosis)
- processes proteins (protein modification) - adds sugar and then packages them into vesicles for transport
What is the structure of lysosomes?
- Spherical sacs surrounded by a single membrane
What is the function of lysosomes?
- contains hydronic digestive enzymes
- breaks down: organelles, ingested material and old cells
What is the structure of mitochondria?
- two membranes separated by a fluid filled space
- inner membranes form cristae
- central part is the matrix
- contains it’s own ribosomes and DNA
Why do mitochondria have their own ribosomes and DNA?
They have their own ribosomes and DNA to make their own enzymes for efficiency.
What is the function of mitochondria?
- produces ATP which releases energy
- carries out aerobic respiration
What is the structure of the centrioles?
- Consists of nine sets of tube like structures that form a wall of cylinders.
- Each tube like structure is composed of three tubes called microtubules.
- They are arranged in triplets.
What is the structure of the chloroplasts?
- Two membranes separated by a fluid filled space
- Inner membrane has flattened sacs called ‘thylakoids’ where chlorophyll is found
- Contain their own ribosomes and DNA
What is the function of the chloroplasts?
- contains chlorophyll to absorb light energy to carry out photosynthesis
What is the structure of the vacuole?
- surrounded by a membrane called the tonoplast
- filled with water and solutes
What is the function of the vacuole?
- helps maintain structure and stability of the cell when turgid
What two groups can prokaryotes be divided into?
- Eubacteria (modern bacteria)
- Archaebacteria
What are the main features of prokaryotes?
1) unicellular
2) smaller ribosomes
3) contain plasmids
4) contain pills
5) may have flagella
6) don’t have any membrane bound organelles (nucleus or ER)
7) no cytoskeleton
What type of cell wall do prokaryotes have?
Peptidoglycan cell wall, not cellulose
Where does respiration occur in prokaryotes?
Mesosomes, not mitochondria
What are plasmids?
Small circular pieces of DNA that can carry genes for antibiotic resistance
What is the capsule in prokaryotes?
A mucus like protective layer that surrounds many pathogenic bacteria.
What is the function of the capsule?
- It protects bacteria from viruses or attacks from a host’s immune system by hiding the antigens on the cell surface.
- It also prevents the cell from drying out
How do flagella move?
They are powered by protein motors and required energy for these protein motors to move.
How can plasmids be transferred to other bacteria?
Bacteria can conjugate with each other by using pilli, plasmids are shared so they both have an antibiotic resistance.
Why don’t prokaryotes have chromosomes?
Their DNA isn’t combined with histone protein (chromosomes are DNA combined with histone protein)
What is the cytoskeleton?
An internal framework which is made up of a network of protien fibres
What is the function of the cytoskeleton?
- provides strength, stability and support
- determines and changes the shape
- moves the membrane
- hold the organelles in place
- helps with movement of organelles
What component is cytoskeleton made up of?
- microfilaments
- microtubules
- centrioles
What are microfilaments made of?
Actin Protein
What is the function of microfilaments?
- These fibres can move against each other which causes movement in some cells
- moves some organelles inside the cell
What are microtubules made of?
Tubulin
Where are microtubules found?
- eukaryotic flagella
- cilia
What are the functions of microtubules?
- can move a microorganism through a liquid
- can waft a liquid past a cell
- other proteins can move organelles along the fibres
What are centrioles?
Structures made of protein fibres which are needed for cell division
What are the similarities between prokaryotic and eukaryotic cells?
- both contain organelles
- their cell surface membrane is made up of a phospholipid bilayer
What are the differences between prokaryotic and eukaryotic cells?
- prokaryotic are single-celled
- eukaryotes are usually larger and more complex
- prokaryotes use binary fission whereas eukaryotes use mitosis and meiosis
- prokaryotes don’t have membrane-bound organelles
What are the differences between fungal cells and plant cells?
- no chloroplasts
- fungal cells can be multicellular
- the cell walls of fungi are made of chitin, not cellulose
What type of bonding is present in water molecules and why?
Hydrogen bonding
- oxygen is more electronegative than hydrogen so it’s a polar covalent bond
What are the properties of water?
- cohesive
- adhesive
- high specific heat capacity
- high specific latent heat
- good solvent
- transparent
- ice is less dense than water
What is cohesion in relation to properties of water?
It is when water molecules form hydrogen bonds with each other to produce the surface tension of water.
What are the benefits of the cohesion of water?
- it explains why the transport stream is maintained in plants
- the surface tension can give some organisms a habitat
What is adhesion in relation the the properties of water?
Adhesion is when water molecules from hydrogen bonds with other molecules such as cellulose.
What is the benefit of water having a high specific heat capacity?
This can reduce the fluctuations of temperature in the organisms body or in their aquatic environments
What is the benefit of water having a high specific latent heat?
It maintains habitats of organisms
Why is water a good solvent and why is that a benefit for organisms?
Water is a good solvent because polar water molecules can be attracted to opposite charged ions.
- therefore it can act as a good transport medium
Why is water being transparent beneficial?
It helps with photosynthesis
Why is it important that ice is less dense than water?
This is important as when lakes freeze only the top layer is frozen, leaving the water below liquid to maintain habitats.
What elements are carbohydrates are made?
- carbon
- hydrogen
- oxygen
What are the examples monosaccharide?
Glucose, fructose, ribose, pentose
What are the examples disaccharide?
Sucrose - glucose + fructose
Lactose - glucose + galactose
Maltose - glucose + glucose
What are the examples polysaccharide?
- glycogen
- amylose
- cellulose
- starch
What is the general formula for carbohydrates?
Cx(H2O)y
How is maltose sugar formed?
It’ s formed from two glucose molecules joined by an alpha 1-4 glycosidic bond
