Biology Topic 2 - Cells As The Basis Of Life

3 pieces of evidence of Endosymbiosis?

1) Mitochondria and Chloroplast are Double Membrane Bounded Organelles

2) They both have ribosomes

3) They both have their own Circular DNA

What are the 4 differences between Eukaryotes and Prokaryotes

Eukaryotes:

1) Contains a nucleus

2) Linear Chromosome

3) Membrane Bound

4) Typically larger

Prokaryotes:

1) Does not contain a nucleus

2) Circular Chromosomes

3) No membrane bound organelles

4) Typically smaller

Name and describe the phases of Mitosis

Prophase: Where the cell nucleus breaks down and dissolves where DNA will condense into chromosomes

Metaphase: The chromosomes line up in the middle of the cell ready for anaphase while spindle fibres extend from centrioles to attach on the centromeres on the chromosomes.

Anaphase: The spindle fibres then pull apart all the chromosomes in half separating the sister chromatids pulling them to opposite sides of the cell retracting to the centrioles

Telophase: The cell begins forming 2 burrows in the middle of the cell, where it will eventually pinch off in the middle separating the 2 cells into 2 daughter cells with identical DNA to its parent cell and to each other.

In what type of cell does mitosis occur?

Eukaryotic Cell

What are the types of Reproduction?

Asexual and Sexual

What are the types of Cell divison?

Mitosis (Eukaryote) and Binary Fission (Prokaryote) as well as meiosis (eukaryotes)

In terms of Mitosis, describe the process of Meiosis

Stage 1 of meiosis is the same as mitosis (Prophase, Metaphase, Anaphase, and Telophase) where additionally maternal and paternal homologous chromosome pairs line up in a random order (independent assortment) with the chance of some paternal and maternal chromosomes having gene sections crossed over. This produces 2 Haploid Daughter Cells at the end of the first stage.

Stage 2 of meiosis is similar to the first stage except there is no DNA replication to begin, The cells goes through Pro, meta, Ana and Telophase where the end product will result in 4 different haploid germ/gamete cells.

Describe Endocytosis and Exocytosis describing what kind of transport they are.

They are: Active Transport

Exocytosis is the process of transporting larger molecules outside of the cell. Vesicles containing material are formed within the Golgi body. After, the cytoskeleton brings it to the edge of the cell to fuse with the membrane and create an opening, allowing material to be released into the extracellular environment.

Endocytosis is the process of transporting larger molecules inside the cell. Molecules bind to receptors on the cell membrane this triggers the cell to create a furrow, and folds around the molecule it then pinches off using the cell membrane and creating a vesicle, the cytoskeleton will then transport the vesicle into a specific place to be used within the cell.

Why is the Metabolic Pathway so important for cells?

As it contains small regulated steps, where at each step there is a small regulated amount of energy released. This small amount of energy in the form of heat energy can therefore be used efficiently. Whereas if all energy were to be released, the excessive heat would denature the cell.

Describe the ATP and ADP + Pi Cycle

ATP is made out of 3 phosphates, where the bond between the 2nd and 3rd phosphate contains energy that can be used in cells. Therefore the bond between the 2nd and 3rd phosphate group is broken to release energy that can be used for cellular processes, this therefore forms ADP + Pi.

In order for ATP to be formed from ADP + Pi, respiration has to occur. As respiration is a metabolic pathway, heat energy is released, this heat energy is then used to support the reforming of the 2nd and 3rd phosphate thus forming ATP.

What are the 4 aspects that occur in a Metabolic Pathway

1. There are many regulated steps within the metabolic pathway.

2. Each step lose energy in the form of heat.

3. Each step produces intermediate compounds

4. Specific enzymes are required at each step.

Why is there multiple regulated steps in a Metabolic Pathway?

Because each step releases a small amount of energy in the form of heat energy rather than a large amount, as if it were in a large amount the excessive heat would cause the enzymes to denature. Additionally the small energy release amount in each step allows the cell to be able to efficiently utilize the energy released.

Describe the process of diffusion and state the type of transport it is.

Diffusion is a passive form of transport which involves the movement of gas and liquid molecules from a high concentrated area to a low concentrated area with the purpose to balance the concentration of a space.

This process does not need a semi-permeable membrane

Describe the process of Osmosis in regards to Aquaporins and what type of transport it is.

Osmosis is the passive process of only water molecules. It is where water move from a low solute concentration (hypotonic) to a high solute concentration (hypertonic) in order to balance solute concentration on both sides of the membrane.

Aquaporins are proteins specifically structured for osmosis, where it is a protein that facilitates water transport across the cell membrane and is important for maintaining water and concentration balance. Aquaporins have a specific structure and properties such as a positive charge internally which allow them to selectively bind to water molecules excluding any other molecules.

Describe the process of Facilitated Diffusion and state the type of transport it is.

Facilitated diffusion is the passive transport of molecules that wouldn’t be able to easily move across the cell membrane (too large or charged molecules). Proteins such as Channel proteins allow this to occur.

What is Sexual Reproduction?

Sexual reproduction occurs through the fusing of sex cells or gametes through fertilisation, where a zygote is formed and the diploid number is restored.

What is Asexual Reproduction?

Asexual reproduction is the production of daughter cells which are genetically identical to the parent cell.
- fragmentation
- cloning
- budding

What is the 3 different Stages of Cell Cycle, and describe them.

G1 Phase: The cell begins to grow

S Phase: DNA synthesis begins to occurs

G2 Phase: The Cell will then continue to grow

Describe Fungal Cells

They are multicellular, contain no chloroplasts, has a cell well, and has a Hyphae Structure.

In terms of SHE what is Application and Limitation?

The benefits it presents to society, and the disadvantages or negatives of the concept.

In terms of SHE what is Influence?

How the concept impacts other areas of other areas and disciplines in society

In terms of SHE what is Development?

The process and improvements of making a new concept, shows how advancements and progress is made.

In terms of SHE what is Communication and Collaboration?

How scientists around the world share information, review research, and work together to solve issues.

Nucleus

The organelle where DNA in the form of chromosomes is found, it also regulates cell growth and production of proteins.

Mitochondria

Acts as the powerhouse for the cell, it is where aerobic respiration takes place and the breakdown of glucose molecules occur to produce ATP molecules. It also has the structure of multiple flattened membrane stacks with lots of enzymes embedded on it, therefore containing more contact points.

Chloroplasts

Rough Endoplasmic Reticulum

Contains lots of ribosomes which are responsible for helping the production of proteins.

Smooth endoplasmic Reticulum

Responsible for the production of lipids.

Nucleolus

Essentially the ribosome factory, where rRNA is transcribed and processed and then combined with proteins to form large and small ribosomal subunits.

Ribosomes

It is the site for protein synthesis, where it converts genetic information from mRNA molecules into a sequence of amino acids.