Topic 3: Voice of the Genome

What’s the function of a Mitochondrion?

It produces energy for the cell and carries out aerobic respiration.

What’s the function of a Plasma Membrane?

A semi-permeable barrier that actively controls what substances enter and leave the cell.

What’s the function of the Nucleus?

Stores genetic material (DNA) and is the site of transcription by mRNA.

What’s the function of the Cell Wall?

Made up of peptidoglycan and maintains the shape of the cell. It also prevents the cell from bursting (Lysis).

What is the function of a Slime Capsule?

It’s a thick polysaccharide layer used for protection against desiccation (drying out) and phagocytosis.

What is the function of a Flagellum?

They contain a motor protein and are used for movement. They are long projections from the cell.

What is the function of a Pili?

Hair-like extensions that enable adherence to surfaces or mediate bacterial conjugation.

What is the function of a Plasmid?

Autonomous circular DNA molecules that can be transferred between bacteria.

What is the function of a Ribosome?

Complexes of RNA and protein that are used for polypeptide synthesis.

What is the function of a Nucleoid?

The region in the cytoplasm where DNA (circular) is stored in Prokaryotic Cells.

What is the function of a Mesosome?

What are some organelles/structures that are only present in Prokaryotic Cells?

Small ribosomes (70s), pili, slime capsules, plasmids, mesosomes, and a cell wall.

What’s the function of a Lysosome?

It’s the site of hydrolysis, digestion, and the breakdown of macro-molecules

What’s the function of Centrioles?

Micro-tubule organizing centers involved with cell division (mitosis, meiosis, and cytokinesis)

What’s the function of a Smooth Endoplasmic Reticulum (Smooth ER)?

Facilitates the synthesis and transport of lipids, steroids, and the metabolism of carbohydrates

What’s the function of a Rough Endoplasmic Reticulum?

It’s studded with ribosomes and facilitates the synthesis and transport of proteins designed for secretion

What’s the function of a Peroxisome?

It catalyses the breakdown of toxic substances, for example hydrogen peroxide or other metabolites

What’s the function of a Nucleolus?

Site of production and assembly of ribosome components

What type of membrane does a Nucleus have?

A double membrane

What type of membrane does a Golgi Apparatus have?

A single membrane

What’s the function of a Golgi Apparatus?

The site of the assembly of vesicles and folded membranes involved in sorting, storing, and modification of secretory products.

What’s the structure of a Mitochondrion?

A double membrane (made of phospholipids) and folds called Cristae on the inner membrane. The space within the inner membrane is called a matrix and the space between the two membranes is called the intermembrane space.

What type of membrane does a Lysosome have?

A single membrane

What’s the function of Chloroplasts?

The site of photosynthesis in plant cells

What’s the equation for Magnification?

Size of image (image) / size of real object (actual)

What’s the equation for Image?

Magnification X size of real object (actual)

What’s the equation for Actual image size?

Size of image (image) / magnification

What’s the definition of resolution?

The smallest distance of separation that can be seen i.e. the smallest distance that two objects still appear as separate objects

How do you convert millimeters (mm) into micrometers (um) and vice versa?

Multiply/Divide by 1000

How do you convert micrometers (um) into nano meters (nm) and vice versa?

Multiply/Divide by 1000

How do you convert millimeters (mm) into nanometers (nm) and vice versa?

Multiply/Divide by 1,000,000

What’s the full process of how genetic code is used to produce a protein that’s secreted?

1. Transcription of DNA to mRNA

2. mRNA leaves nucleus and binds to Ribosomes

3. Ribosomes translate the mRNA and produce the polypeptide

4. The polypeptide moves through the Rough ER where it is folded into a 3-D/tertiary shape (becoming a protein)

5. Transport Vesicles fuse to the Rough ER and pinch off the section containing the protein

6. Transport Vesicles from the Rough ER fuse to the Golgi Apparatus

7. Proteins are modified within the Golgi Apparatus

8. Transport Vesicles pinch off the section of the Golgi Apparatus containing the modified protein

9. Transport Vesicles fuses to the cell surface membrane and releases the modified protein

What is the Cell Cycle?

A sequence of tightly regulated and precisely timed cell reactions that results in the growth of cells and replication of genetic material.

What are the 3 phases of the Cell Cycle?

Interphase, Mitotic Phase, and Cytokinesis

What the sub-phases of Interphase

Gap 1 (G1) Phase, Synthesis (S) Phase , and the Gap 2 (G2) phase. There’s also a Gap 0 (G0) phase and checkpoints at the end of the G1 and G2 phases and one in the middle of the Mitosis phase.

What is the purpose of the checkpoints?

To ensure all the cells/dna are functioning and have been duplicated correctly. If they haven’t been they are either corrected or destroyed. They can be destroyed via apoptosis.

What is Apoptosis?

It’s programmed cell death, essentially cell self-destruction.

What occurs during the G0 Phase?

Cell cycle arrest occurs. Cells go about their functions and don’t duplicate further.

What occurs during the G1 Phase?

A cell prepares to replicate DNA by synthesising the mRNA and proteins required in future steps. The cell grows larger and some organelles duplicate.

What occurs during the S Phase?

The genetic information within the cell duplicates via the process of DNA replication. Sister Chromatids are produced, which are identical pairs of chromosomes. The Sister Chromatids are attached to each other by a centromere, a special sequence of DNA used to link sister chromatids. Important during Mitosis.

What occurs during the G2 Phase?

The cell undergoes additional growth, replenishes energy, and reorganises it’s cytoplasmic components for division. Some organelles are duplicated. This phase ends when Mitosis begins.

What are the sub-phases of Mitosis?

Prophase, Metaphase, Anaphase, and Telophase. Cytokinesis is the end phase of Mitosis and cells either go into the G0 phase or the G1 phase.

What occurs during Prophase?

1. The chromosomes condense, becoming short and thick

2. Two strands called chromosomes make up the Chromatid (replicated chromosome) and are identical to each other

3. Centrioles move around the nuclear envelope and position themselves on either side of the cell

4. Spindle fibers, made from microtubules from cytoplasm, form between the two centrioles

5. The nuclear envelope around the DNA breaks signalling the end of prophase and beginning of metaphase

What occurs during Metaphase?

1. The breakdown of the nuclear envelope signals the end of prophase and beginning of metaphase

2. The chromatids’ centromeres attach to the spindle fibres

3. They are positioned along the metphase plate of the cell, essentially lining up in the middle of the cell

What occurs during Anaphase?

1. The centromeres split and the spindle fibres shorten, pulling the two halves apart

What occur during Telophase?

What occurs during Cytokinesis?