Why are some genes expressed and some not?
Only a fraction of the genes in a cell are expressed at any one time. The variety of gene expression profiles characteristic of different cell types arise because these cells have distinct sets of transcription regulators. Some of these regulators work to increase transcription, whereas others prevent or suppress it.
Why can’t eukaryotic genes express protein in bacteria?
coli for expression of eukaryotic genes is that it is a prokaryote, and therefore lacks the membrane-bound nucleus (and other organelles) found in eukaryotic cells. This means that certain eukaryotic genes may not function in E.
Why do eukaryotes not have operons?
When an operon is transcribed, all of the genes on the operon are on the same mRNA. Operons occur in prokaryotes, but not eukaryotes. In eukaryotes, each gene is made on individual mRNAs and each gene has its own promoter. Cells can’t afford to waste energy making genes if they don’t need them.
Is human prokaryotic?
The human body is a combination of both prokaryotes and eukaryotes. The human body contains a large number of prokaryotes. In the real sense of it, the number of prokaryotes in the human body exceeds the number of human cells present in the body. Prokaryotes do not only live in the human body.
Are humans protists?
Plant-like protists produce almost one-half of the oxygen on the planet through photosynthesis. Other protists decompose and recycle nutrients that humans need to live. Humans use protists for many other reasons: Many protists are also commonly used in medical research.
What is unique about the Protista kingdom?
Protists are eukaryotes, which means their cells have a nucleus and other membrane-bound organelles. Most, but not all, protists are single-celled. These unique organisms can be so different from each other that sometimes Protista is called the “junk drawer” kingdom.
What is the body type of most protist?
Cell Structure The cells of protists are among the most elaborate and diverse of all cells. Most protists are microscopic and unicellular, but some true multicellular forms exist. A few protists live as colonies that behave in some ways as a group of free-living cells and in other ways as a multicellular organism.
What is the purpose of protists?
Protists produce almost one-half of the oxygen on the planet through photosynthesis, decompose and recycle nutrients that humans need to live, and make up a huge part of the food chain. Humans use protists for many other reasons: Many protists are also commonly used in medical research.
What are the main characteristics of Kingdom Protista give examples?
Outline the characteristics of Kingdom Protista.
- All protists are eukaryotic organisms.
- Most protists are aquatic, others are found in moist and damp environments.
- Most are unicellular, however, there are a few multicellular protists such as the giant kelp.
- They may be autotrophic or heterotrophic in nature.
What is the mode of nutrition in Kingdom Protista?
The major modes of nutrition among protists are autotrophy (involving plastids, photosynthesis, and the organism’s manufacture of its own nutrients from the milieu) and heterotrophy (the taking in of nutrients).
What is the scientific name for Protista?
This organism consists of a single cell with several flagella. Therefore, this organism belongs to the domain Eukarya, the domain that includes humans. This particular eukaryote is one of the smallest, simplest organisms in the domain, called a protist. It’s scientific name is Giardia lamblia.
Does a protist have DNA?
Like all other eukaryotes, protists have a nucleus containing their DNA. They also have other membrane-bound organelles, such as mitochondria and the endoplasmic reticulum.
Do fungi contain DNA?
Fungi are eukaryotes and have a complex cellular organization. As eukaryotes, fungal cells contain a membrane-bound nucleus where the DNA is wrapped around histone proteins. A few types of fungi have structures comparable to bacterial plasmids (loops of DNA).