PASS week 3 questions Flashcards
- Which of the following is not true?
a. Genes are encoded on DNA
b. DNA stands for deoxyribonucleuic acid
c. Genes are encoded on proteins
d. DNA is the central molecule of life
- Which of the following is not true?
a. Genes are encoded on DNA
b. DNA stands for deoxyribonucleuic acid
c. Genes are encoded on proteins NOT TRUE (genes encode proteins)
d. DNA is the central molecule of life
Please provide a brief description of bacterial and eukaryotic cells and distinguish the differences between these cells. Attempt to draw a simple picture of the cells general structure.
(Pretty picture of Prokaryote cell here) Prokaryotic: small, naked DNA in the cytoplasm. Does NOT have a cell nucleus. Prokaryotic cells do not have membrane-bounded organelles like mitochondria, choloroplasts, an endoplasmic reticulum, or a nucleus.
Eukaryotic: large, complex internal structure with organelles and a membrane-bounded nucleus containing DNA and have an internal membrane structure that separates and forms their organelles. Unique features include lysosomes, centrioles and flagella (in some plant sperm)
What is the classification of organisms based on? Provide an example
a. Based on cellular structure and organisation.
b. The word prokaryote comes from the Greek pro- (before) + karyon (nut or kernel), referring to the lack of a cell nucleus. The work eukaryote which comes from the Greek eu- (good/true), and karyon (nut or kernel), referring to the cell nucleus.
- Which of the follow is not true?
a. Extracellular components and connections between cells help coordinate cellular activities
b. Prokaryotic cells have an additional phase in DNA transcription called RNA processing
c. The endomembrane system regulates protein traffic and performs metabolic function in the cell
d. The eukaryotic cell’s genetic instructions are housed in the nucleus
- Which of the follow is not true?
a. Extracellular components and connections between cells help coordinate cellular activities
b. NOT TRUE: Prokaryotic cells have an additional phase in DNA transcription called RNA processing
c. The endomembrane system regulates protein traffic and performs metabolic function in the cell
d. The eukaryotic cell’s genetic instructions are housed in the nucleus
Describe the structure and function of the following in the eukaryotic cell: Cytoskeleton
Cytoskeleton: The cytoskeleton is a network of fibres that organises structures and activities in the cell
Describe the structure and function of the following in the eukaryotic cell: Mitochondria
Mitochondria: change energy from one from to another. The site of respiration (the process of harvesting energy from food molecules)
Describe the structure and function of the following in the eukaryotic cell: Nucleus
c. Nucleus: surrounded by a double nuclear membrane which is perforated by pores. Contains DNA and protein (chromatin)
Describe the structure and function of the following in the eukaryotic cell: Nucleolus
d. Nucleolus: the site where ribosome units are assembled and made.
Describe the structure and function of the following in the eukaryotic cell: Ribosomes
Ribosomes: perform protein synthesis. They read mRNA and produce encoded protein (called translation). They consist of a large and small subunit. 2 membranes. The outer is smooth, while the inner is folded into cristae or shelf-like structures.
Describe the structure and function of the following in the eukaryotic cell: Endoplasmic reticulum
Endoplasmic reticulum: A membrane system continuous with the outer membrane of nucleus. The Rough ER harbours ribosomes. This means it is a major organelle for protein synthesis. The Smooth ER does not participate in protein synthesis. Instead, it synthesises lipids, including cholesterol and phospholipids for the production of cell membranes.
Give a brief description of the structure of the chromosome, exterior, capsule and flagella of prokaryotic cells
a. The bacteria chromosome is a single, circular molecule
b. The exterior of the prokaryotic cell is rigid and multilayered. The peptidoglycan of the bacterial cell wall defines the cell shape
c. The capsule is the cells bacterial force field. The capsule is an external layer of polysaccharide on the outside of the cell. The capsule prevents desiccation of the bacteria and assists in maintaining bacterial immunity to bacteriophages.
d. Flagella and pili are used for motility and attachment
True or False?
a. The Eukaryotic have been around the longest compared to the Prokaryotic. True/ False?
b. It is believed some organelles have prokaryotic origin. True/ False
c. Prokaryotes and mitochondria/chloroplasts are about the same size. True/ False
a. The Eukaryotic have been around the longest compared to the Prokaryotic. FALSE
b. It is believed some organelles have prokaryotic origin. TRUE
c. Prokaryotes and mitochondria/chloroplasts are about the same size. TRUE
List 4 functions of the cell membrane
- Encloses and protects the cell contents (forms barrier between inside and outside of the cell but has selective permeability)
- Provides and supports mechanical structure (cytoskeleton, ECM, defines and encloses the cell)
- Allows transport in and out of the cell (active, passive, bulk transport (exocytosis, endocytosis)
- Markers & Signaling (due to surface proteins and receptors embedded within the cell membrane – which allow for communication and interaction with specific chemicals)
- Metabolic activities -> enzyme proteins that perform some metabolic activities are in the membrane
Describe the term ‘amphipathic’
Defined as a molecule that has both hydrophilic and hydrophobic components; able to interact with both polar and non-polar substances. From the Greek ‘amphi’ (on both sides) and ‘pathikos’ (suffering or remaining passive)
Fill in the blanks:
Cellular membranes are xxxxx mosaics made up of xxxx and xxxx. Membrane structure results in xxxxxx permeability.
Cellular membranes are fluid mosaics made up of lipids and proteins. Membrane structure results in selective permeability.
