Which one of the following human cells is devoid of a nucleus?
Cell
2. Consider the following statements about stem cells : 1. Stem cells h
Consider the following statements about stem cells :
- 1. Stem cells have the potential for self-renewal via mitotic cell division.
- 2. In 1908, James Thomas and his colleagues first derived human embryonic stem cells from donated blastocysts through in vitro fertilization.
Which of the statements given above is/are correct?
3. Which one of the following cell organelles is not lined by membrane ?
Which one of the following cell organelles is not lined by membrane ?
– Ribosome: Composed of ribosomal RNA (rRNA) and proteins, not enclosed by a membrane.
– Nucleus: Enclosed by a double membrane (the nuclear envelope).
– Golgi Apparatus: Composed of membrane-bound sacs (cisternae), lined by a single membrane.
4. In a mammalian cell, the protein is synthesized by
In a mammalian cell, the protein is synthesized by
5. Which of the following organelle(s) in an animal cell would have DNA a
Which of the following organelle(s) in an animal cell would have DNA and RNA?
– Eukaryotic cells also contain DNA in certain organelles: mitochondria (mitochondrial DNA or mtDNA) and, in plant cells and some other eukaryotes, chloroplasts (chloroplast DNA or cpDNA). Animal cells lack chloroplasts.
– RNA (Ribonucleic Acid) is involved in protein synthesis and other cellular processes. Various types of RNA (mRNA, tRNA, rRNA) are transcribed from DNA.
– In animal cells:
– Nucleus: Contains the main genome (DNA) and is where transcription occurs, producing various types of RNA. Thus, the nucleus has both DNA and RNA.
– Mitochondria: Contain their own circular DNA (mtDNA) and also have ribosomes (mitoribosomes) made of ribosomal RNA (mt-rRNA) and proteins, and produce their own mRNA and tRNA. Thus, mitochondria have both DNA and RNA.
– Ribosomes: Are complex molecular machines responsible for protein synthesis. They are composed of ribosomal RNA (rRNA) and proteins. Ribosomes themselves do not contain DNA. They read mRNA to build proteins.
– Therefore, in an animal cell, the nucleus and mitochondria are the organelles that contain both DNA and RNA.
6. Which one of the following cell organelles synthesizes its own protein
Which one of the following cell organelles synthesizes its own proteins involving genes present in its DNA?
7. Which of the following statements are correct regarding the general di
Which of the following statements are correct regarding the general difference between plant and animal cells ?
- 1. Plant cells have cellulose cell walls whilst animal cells do not.
- 2. Plant cells do not have plasma membrane unlike animal cells which do.
- 3. Mature plant cell has one large vacuole whilst animal cell has many small vacuoles.
Select the correct answer using the code given below :
8. Which one of the following structure is NOT found in prokaryotes ?
Which one of the following structure is NOT found in prokaryotes ?
– The genetic material (DNA) in prokaryotes is located in a region called the nucleoid, which is not enclosed by a membrane.
– The nuclear envelope is the double membrane that surrounds the nucleus in eukaryotic cells.
9. Both starch and glycogen are made up of glucose, however:
Both starch and glycogen are made up of glucose, however:
– Starch is found in plants.
– Glycogen is found in animals and fungi.
10. The rate of an enzyme catalyzed reaction depends :
The rate of an enzyme catalyzed reaction depends :
– Substrate concentration affects the frequency of enzyme-substrate collisions and active site saturation.
– pH affects the ionization states of enzyme and substrate, influencing activity.
– Temperature affects molecular kinetic energy and enzyme stability (denaturation).