MDCAT Biology (1st Year) Unit 4

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Preparation for MDCAT 2023 Biology Unit 4.

What is the significance of the cell's nucleus?

1 point

It contains cytoplasm

It provides structural support to the cell

It was discovered by Robert Hooke

It changed the perception of the cell as an empty space

Clear selection

Who proposed the idea that all living beings originate from or consist of cells?

1 point

Robert Hooke

Lorenz Oken

Jean Baptist de-Lamarck

Theodor Schwann

Clear selection

What are the three basic parts of a cell according to the Cell Theory?

1 point

Nucleus, cytoplasm, cell wall

Nucleus, cytoplasm, plasma membrane

Nucleus, mitochondria, cell wall

Nucleus, ribosomes, plasma membrane

Clear selection

Who independently came up with the Cell Theory?

1 point

Robert Hooke and Jean Baptist de-Lamarck

Theodor Schwann and Schleiden

Lorenz Oken and Robert Brown

Jean Baptist de-Lamarck and Theodor Schwann

Clear selection

What is the main difference between plant cells and animal cells, according to the Cell Theory?

1 point

Plant cells have nuclei, while animal cells do not.

Plant cells have a plasma membrane, while animal cells do not.

Plant cells have cell walls, while animal cells do not.

Plant cells have cytoplasm, while animal cells do not.

Clear selection

What was the significant contribution of Louis Pasteur to the cell theory?

1 point

He proposed the concept of abiogenesis.

He discovered the chemical composition of cells.

He demonstrated the division of cells by mitosis.

He provided experimental proof for cell division.

Clear selection

Which scientist's hypothesis challenged the idea of abiogenesis and proposed the concept of cells arising from existing cells?

1 point

Rudolph Virchow

Louis Pasteur

August Weismann

Robert Hooke

Clear selection

What is the basis for the working definition of living things?

1 point

They can reproduce themselves.

They have a common origin.

They arise spontaneously from nonliving things.

They are composed of cells.

Clear selection

In a compound microscope, the resolution is approximately how many times greater than that of the naked eye?

1 point

50X

100X

500X

1000X

Clear selection

What determines the magnification power of a microscope?

1 point

Source of illumination

Type of lenses used

X value of the ocular lens

Resolution of the microscope

Clear selection

In an electron microscope, how does the resolution compare to that of a compound microscope?

1 point

It is the same as a compound microscope.

It is 2-4 times greater.

It is 500 times greater.

It is 250,000 times greater.

Clear selection

What is the main factor that determines the source of illumination in a microscope?

1 point

Resolution of the microscope

Type of sample being observed

Magnification power of the microscope

Type of microscope being used

Clear selection

What is the significance of the cell theory in biology?

1 point

It explains the concept of abiogenesis.

It defines the basic chemical composition of living things.

It demonstrates the versatility of cells.

It serves as a unifying concept in biology.

Clear selection

What is the central idea behind the statement "All cells arise from pre-existing cells" in the Cell Theory?

1 point

Cells are immortal and never die.

New cells can spontaneously form from non-living matter.

Cells reproduce through a process called mitosis.

Cells are generated by the division of pre-existing cells.

Clear selection

Which of the following is NOT a function of muscle cells in animals?

1 point

Transmitting impulses

Contraction and relaxation

Secretion of gastric juice

Carrying oxygen

Clear selection

What process involves the separation of cell components based on their size and density using a centrifuge?

1 point

Cell division

Cell fractionation

Cell respiration

Cell differentiation

Clear selection

Which organelle is responsible for conducting water and mineral salts in plants?

1 point

Mitochondria

Xylem cells

Chloroplasts

Nucleus

Clear selection

How are cells of animals and plants different from prokaryotic cells?

1 point

They have a distinct nucleus.

They lack a plasma membrane.

They are smaller in size.

They contain only cytoplasm.

Clear selection

What is the basic unit of structure and function in living organisms, according to the text?

1 point

Tissues

Organs

Cells

Nuclei

Clear selection

What is the size of one nanometer (nm) in meters?

1 point

0.000001 meter

0.001 meter

0.00001 meter

0.000000001 m

Clear selection

In cell fractionation, how are different cellular components separated?

1 point

By color

By temperature

By size and weight

By electrical charge

Clear selection

Which of the following is NOT a component of a generalized cell?

1 point

Nucleus

Cytoplasm

Plasma membrane

Cell wall

Clear selection

Which statement accurately describes the difference between eukaryotic and prokaryotic cells?

1 point

Eukaryotic cells lack a nucleus.

Prokaryotic cells have a distinct nucleus.

Eukaryotic cells are larger in size.

Prokaryotic cells have a plasma membrane.

Clear selection

What is the primary chemical composition of the cell membrane?

1 point

Carbohydrates

Proteins

Lipids

Nucleic acids

Clear selection

Which term describes the structural arrangement of proteins in the cell membrane?

1 point

Unit Membrane Model

Protein Sandwich Model

Fluid Mosaic Model

Lipid Bilayer Model

Clear selection

The term "differentially permeable" or "selectively permeable" refers to the cell membrane's ability to:

1 point

Allow all substances to pass through equally

Prevent the passage of all substances

Allow only lipid-soluble substances to pass

Allow only specific substances to pass through

Clear selection

Which type of transport requires energy and moves substances against their concentration gradient?

1 point

Passive transport

Facilitated diffusion

Active transport

Osmosis

Clear selection

What provides the energy for active transport?

1 point

Carbohydrates

ATP (Adenosine triphosphate)

Lipids

Proteins

Clear selection

In neurons (nerve cells), what is the primary function of the cell membrane?

1 point

Regulating passage of water

Storing energy

Transmitting nerve impulses

Producing proteins

Clear selection

What is the term for the process by which the cell membrane engulfs solid particles?

1 point

Exocytosis

Pinocytosis

Active transport

Phagocytosis

Clear selection

Which molecules can easily cross the cell membrane due to their lipid solubility?

1 point

Ions

Charged particles

Lipids

Glucose

Clear selection

What is the primary function of the cell membrane's charged pores?

1 point

Transmitting nerve signals

Regulating water flow

Facilitating passive transport

Allowing movement of materials

Clear selection

Which of the following is NOT a component of the primary cell wall in plant cells?

1 point

Cellulose

Pectin

Hemicellulose

Lignin

Clear selection

The primary wall of a plant cell is composed of cellulose, pectin, and:

1 point

Chitin

Silica

Peptidoglycan

Lysosome

Clear selection

The strengthening material in the prokaryotic cell wall is

1 point

Lignin

Cellulose

Chitin

Peptidoglycan

Clear selection

The middle lamella is primarily composed of:

1 point

Cellulose

Pectin

Lignin

Chitin

Clear selection

Which layer of the cell wall is formed first in between neighboring plant cells?

1 point

Primary wall

Secondary wall

Middle lamella

Tertiary wall

Clear selection

What is the primary function of the cell wall?

1 point

Facilitating cytoplasmic streaming

Regulating material passage

Providing shape and rigidity

Synthesizing cytoplasm

Clear selection

The aqueous ground substance of the cytoplasm, containing various organelles and inclusions, is called:

1 point

Nucleus

Cytosol

Endoplasmic reticulum

Golgi complex

Clear selection

Which of the following is NOT a part of the cytoplasmic streaming movement?

1 point

Mitochondria

Nucleus

Endoplasmic reticulum

Lysosomes

Clear selection

The main function of the cytoplasm is to:

1 point

Act as a barrier to material passage

Store vital chemicals

Form cell walls

Regulate metabolic processes

Clear selection

Which organelles are responsible for the movement within the cytoplasm through cytoplasmic streaming?

1 point

Nuclei

Mitochondria

Centrioles

Golgi complexes

Clear selection

What is the primary function of the smooth endoplasmic reticulum (SER)?

1 point

Synthesis of proteins

Metabolism of lipids

Detoxification of harmful drugs

Transmission of impulses in muscle cells

Clear selection

Which cellular structure is responsible for the synthesis of proteins and is often associated with rough endoplasmic reticulum (RER)?

1 point

Ribosomes

Golgi apparatus

Nucleolus

Nucleus

Clear selection

The spherical or tubular membranes that separate the material present in the endoplasmic reticulum from the cytoplasmic materials are called:

1 point

Nucleoli

Cisternae

Ribosomes

Vesicles

Clear selection

Which component is essential for the attachment of ribosomal subunits to form an 80S ribosome particle?

1 point

RNA

DNA

Mg2+ ions

Golgi apparatus

Clear selection

Which of the following is NOT a function of the endoplasmic reticulum?

1 point

Protein synthesis

Lipid metabolism

Transmission of impulses

Mechanical support

Clear selection

The rough endoplasmic reticulum (RER) is primarily involved in:

1 point

Lipid metabolism

Detoxification of drugs

Protein synthesis

Mechanical support of the cell

Clear selection

In which form of endoplasmic reticulum are ribosomes attached to the membranes?

1 point

Smooth ER

Nucleolar ER

Rough ER

Golgi ER

Clear selection

The function of ribosomes is primarily associated with:

1 point

Metabolism of lipids

Detoxification of drugs

Protein synthesis

Impulse transmission

Clear selection

Which cellular structure is responsible for assembling new ribosomes?

1 point

Endoplasmic reticulum

Nucleolus

Golgi apparatus

Cytoplasm

Clear selection

Which of the following is a component of eukaryotic ribosomes?

1 point

Lipids

DNA

Proteins

Polysaccharides

Clear selection

What is the primary function of the Golgi Apparatus in eukaryotic cells?

1 point

Energy production

Phagocytosis

Protein modification and packaging

DNA replication

Clear selection

Which surface of the Golgi cisternae is responsible for modifying and packaging molecules?

1 point

Outer convex surface

Inner concave surface

Forming face

Maturing face

Clear selection

What is the relationship between the Golgi Apparatus and lysosomes?

1 point

Golgi Apparatus produces lysosomes

Lysosomes process enzymes for the Golgi Apparatus

Golgi Apparatus is involved in the formation of lysosomes

Lysosomes replace Golgi Apparatus in some cells

Clear selection

Which organelle is responsible for phagocytosis and contains enzymes for breaking down foreign objects?

1 point

Mitochondria

Lysosomes

Golgi Apparatus

Endoplasmic reticulum

Clear selection

Which process involves the engulfment of parts of a cell by lysosomes for recycling and renewal?

1 point

Phagocytosis

Exocytosis

Autophagy

Endocytosis

Clear selection

What is the main role of lysosomal enzymes

1 point

Protein synthesis

ATP production

Digestion of food particles

DNA replication

Clear selection

In the Golgi complex, what is the outer convex surface of the cisternae called?

1 point

Maturing face

Forming face

Golgi face

Fusion face

Clear selection

Which organelle is known for being involved in the secretion of cell products and converting proteins into glycoproteins?

1 point

Mitochondria

Endoplasmic reticulum

Golgi Apparatus

Nucleus

Clear selection

What is the significance of lysosomes in cellular processes?

1 point

Production of energy

DNA replication

Recycling of cellular components

Oxygen transport

Clear selection

Which term refers to the process where lysosomes release enzymes for digestion outside the cell?

1 point

Phagocytosis

Autophagy

Exocytosis

Endocytosis

Clear selection

Which organelle contains oxidative enzymes such as peroxidase and catalase?

1 point

Nucleus

Golgi apparatus

Mitochondria

Peroxisomes

Clear selection

What is the primary function of peroxisomes in a cell?

1 point

Photosynthesis

Protein synthesis

Formation and decomposition of hydrogen peroxide

Carbohydrate metabolism

Clear selection

Which organelle is most abundant in plant seedlings and is involved in the conversion of stored fatty acids to carbohydrates?

1 point

Mitochondria

Nucleus

Glyoxysomes

Vacuoles

Clear selection

In which type of plant seed are glyoxysomes primarily involved in the breakdown of fatty acids?

1 point

Lipid-rich seeds

Lipid-poor seeds

Both types of seeds equally

None of the above

Clear selection

What is the main role of vacuoles in plant cells?

1 point

ATP production

Storage of genetic material

Expansion of the cell volume

Formation of cell membranes

Clear selection

Question 5: Which process involves the engulfment of parts of a cell by lysosomes for recycling and renewal?

1 point

Phagocytosis

Exocytosis

Autophagy

Endocytosis

Clear selection

Which organelle contributes significantly to the turgor that provides support for plant cells?

1 point

Nucleus

Chloroplasts

Vacuoles

Peroxisomes

Clear selection

Which statement is true about peroxisomes?

1 point

They have a double membrane structure.

They are absent in plant cells.

They play a role only in anabolic pathways.

They contain enzymes involved in hydrogen peroxide metabolism.

Clear selection

Which organelle is characterized by its involvement in both catabolic and anabolic pathways in plants?

1 point

Mitochondria

Nucleus

Golgi apparatus

Peroxisomes

Clear selection

What is the approximate diameter of peroxisomes?

1 point

0.5 nm

5 nm

50 nm

500 nm

Clear selection

What is the primary reason for naming the organelle "peroxisome"?

1 point

It is rich in peroxidase enzymes.

It produces hydrogen peroxide.

It contains oxidative enzymes.

It is involved in lipid metabolism.

Clear selection

What are the main proteins present in the cytoskeleton?

1 point

Actin and myosin

Tubulin and actin

Actin and tropomyosin

Tubulin and myosin

Clear selection

Which organelles are derived from special assemblies of microtubules?

1 point

Mitochondria

Chloroplasts

Centrioles

Ribosomes

Clear selection

Which organelle is responsible for the manufacture and supply of energy to the cell?

1 point

Nucleus

Centriole

Mitochondrion

Chloroplast

Clear selection

What is the primary function of microfilaments?

1 point

Determination of cell shape

Formation of cilia

Internal cell motion

Assembly of the spindle structure

Clear selection

Which type of plastid contains a green pigment called chlorophyll?

1 point

Leucoplasts

Chromoplasts

Chloroplasts

Amyloplasts

Clear selection

Which component of the chloroplast is responsible for trapping sunlight energy and forming ATP?

1 point

Stroma

Envelope

Thylakoids

Grana

Clear selection

What is the primary function of centrioles?

1 point

Photosynthesis

Cell division and furrow formation

Energy production

Protein synthesis

Clear selection

What is the main role of microtubules during mitosis?

1 point

Formation of cilia

Internal cell motion

Determination of cell shape

Assembly and disassembly of the spindle structure

Clear selection

Which organelle contains both DNA and ribosomes?

1 point

Nucleus

Mitochondrion

Chloroplast

Centriole

Clear selection

Which protein is linked to the inner face of the plasma membrane and makes up microfilaments?

1 point

Tubulin

Myosin

Actin

Tropomyosin

Clear selection

What is the primary function of chromoplasts in plants?

0 points

Energy production

Storage of food

Photosynthesis

Imparting colors other than green

Clear selection

Where are leucoplasts primarily found in plants?

1 point

Petals of flowers

Leaves

Underground parts

Stems

Clear selection

What is the function of the nucleus in a cell?

1 point

Energy production

Storage of food

Control of cell activities

Photosynthesis

Clear selection

Which of the following types of cells is likely to have more than one nucleus?

1 point

Plant cells

Animal cells

Cells in non-dividing stage

Cells in dividing stage

Clear selection

In which type of cell is the nucleus generally pushed towards the periphery?

1 point

Animal cells

Plant cells

Dividing cells

Non-dividing cells

Clear selection

What is the function of nucleoli in the nucleus?

1 point

Energy production

Synthesis of ribosomal RNA

Storage of DNA

Photosynthesis

Clear selection

Which part of the nucleus separates it from the cytoplasm?

1 point

Nuclear membrane

Nucleolus

Chromosomes

Nucleoplasm

Clear selection

What is the function of nuclear pores?

1 point

Synthesis of DNA

Control of cell division

Exchange of materials between nucleus and cytoplasm

Photosynthesis

Clear selection

Which cellular component is composed of ribosomal RNA (rRNA)?

1 point

Chloroplast

Chromoplast

Nucleolus

Nucleus

Clear selection

Question: In which type of cells are nucleoli more likely to be numerous?

1 point

Differentiated cells

Undifferentiated cells

Animal cells

Plant cells

Clear selection

What is the term for the thread-like structures that form when chromatin material is converted during cell division?

1 point

Centromeres

Chromatids

Spindle fibers

Genes

Clear selection

Which part of a chromosome is responsible for attaching spindle fibers during cell division?

1 point

Arms

Centromere

Chromatid

Chromatin

Clear selection

What is the composition of a chromosome?

1 point

Proteins only

DNA only

RNA and proteins

DNA and proteins

Clear selection

In which part of the cell are genes located, carrying information to control cell activities?

1 point

Nucleus

Cytoplasm

Centromere

Chromatids

Clear selection

What is the term for the specific number of chromosomes present in all individuals of the same species?

1 point

Chromatid number

Diploid number

Haploid number

Centromere number

Clear selection

Which cells contain the haploid chromosome number?

1 point

Muscle cells

Skin cells

Germ cells

Nerve cells

Clear selection

What is a distinctive feature of prokaryotic cells compared to eukaryotic cells?

1 point

Presence of a nucleus

Double nuclear membrane

Presence of mitochondria

Lack of nuclear membrane

Clear selection

Which organisms possess prokaryotic cells?

1 point

Animals and plants

Fungi and protista

Bacteria and blue-green algae

Humans and chimpanzees

Clear selection

Which structure is absent in prokaryotic cells but present in eukaryotic cells?

1 point

Ribosomes

Golgi apparatus

Cell wall

Mitochondria

Clear selection

What is the primary component of the cell wall in prokaryotic cells?

1 point

Cellulose

Murein

Peptidoglycan

Sacculus

Clear selection

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