Question

What are the functions of the plasma membrane? How does the function differ between bacteria and eukaryotic cells?

How does DNA differ between bacteria and eukaryotic cells?

What is the function of ribosomes? What is the composition of ribosomes? How does it differ between prokaryotes and eukaryotes?

What is a cytoplasm?

What are the 2 main classes of reactions in cells?

What is the energy currency of cells? Why? Be able to explain this in terms of structure.

What is energy coupling?

What are all the functions for each carbon compound? Be able to name a specific one for each function.

What are the levels of protein structure? Anything that happens in the cell is due to protein Proteins function:

   Proteins function:

Structure:

Transport:

Protection/Defense:

Control/regulation:

Catalysis: catalase

Movement:

Storage:

Answer 1

ans.1 ) functions of plasma membrane

1. plasma membrane saperates the components of the cell from its outside environment.

2. it regulates what enters and exits the cells.

3. it allows only selected substances into the cell and keeps others out.

4. plasma membrane has a major role in protecting the integrity of the interior of the cell.

5. plasma membrane serves as a base of attatchment for the cytoskeleton in some organism and cell walls in other organisms.

Thus it supports the cell and helps in maintaining the shape of the cell.

functions of plasma membrane in bacteria which differs from eukaryotic cells are :-

Energy generating functions, involving respiratory and photosynthetic electron transport systems, estabalistment of proton motive force, and transmembranous, ATP synthesizing ATPase.

Ans.2 ) prokaryotic vs eukaryotic DNA

Prokaryotic DNA

1. it is found freely in the cytoplasm.(within the region called the nucleoid)

2. It is naked( not bound with protein and therefore doesnot form chromatin)

3. Genomes are compact ( contain little repetetive DNA and no introns)

4. It contains extra chromosomal plasmids

5. It is circular in shape

Eukaryotic DNA

1. It is contained with in the nucleus.

2. It is bound to histone proteins

3. Genome contain large amounts of non coding and repetitive DNA.

4. Do not contain plasmids(but organelles such as mitochondria may contain their own chromosome)

5. These are linear in shape.

ans.3 functions of ribosome

1. they assemble amino acids to form specific proteins., proteins are essential to carry out cellular activities.

2.the process of production of proteins, the deoxyribonucleic acid produces mRNA by the process of DNA transcription.

3. the genetic message from the mRNA is translated into proteins during DNA translation.

4. the sequences of protein assembly during protein synthesis are specified in mRNA.

5. the mRNA is synthesized in the nucleus and is transported to the cytoplasm for further process of protein synthesis.

composition of ribosomes

1. typically ribosomes are composed of 2 subunits : a large subunit and a small subunit.

2. the subunits of ribosomes are synthesized by the nucleolus.

3. the subunits of ribosomes are join together when the ribosomes attatches to the messenger RNA during the process of protein synthesis.

4.Ribosomes along with a transfer RNA molecules helps to translate the protein coding genes in mRNA to proteins.

differences among eukaryotic and prokaryotic ribosomes

eukaryotic ribosomes are larger. They consist of a 60S large subunit and a 40S small subunit, which come together to form an 80S particle having mass of 4200kd, compared with 2700kd mass for the prokaryotic 70S ribosomes.

the 40S subunits contains an 18S RNA that is homologous to the prokaryotic 16S RNA.

the 60S subunit contains three RNAs and 5S and 28S RNAs are the counterparts of the prokaryotic 5S and 23S molecules its 5.8S RNA is unique to eukaryotes.

ans.4 Cytoplasm

in cell biology , the cytoplasm is the material within the living cell, excluding the cell nucleus.

it comprises cytosol and cell organelles - the cell's internal sub-structures .

all of the contents of prokaryotic organism are contained with in the cytoplasm.

with in the cells of eukaryortic organism the content of the cell nucleus are saperated saperated from the cytoplasm, and are then called nucleoplasm.

the cytoplasm is about 80% water and usually colorless.