Biology Practice test

The earliest cells detectable in fossils were different from the cells in animals, plants, fungi, and protists living today. These first prokaryotic cells gave rise to eukaryotic cells approximately 1.7 billion years ago. The structure of eukaryotic cells today suggests how they might have evolved from their prokaryotic ancestors. Scientists examining mitochondria and chloroplasts now think that these organelles were probably free-living prokaryotes before becoming a part of eukaryotic cells long ago. Which of the following is a characteristic of chloroplasts that suggests that they might have evolved from free-living bacteria?

Chloroplasts have their own DNA.

__________ is the self-replicating material present in nearly all living organisms; it is the main constituent of chromosomes and the carrier of genetic information.

DNA

identify the cellular structures and their functions in this diagram of a eukaryotic cell?

Go look at a diagram

The endomembrane system includes ________.

Golgi apparatus, lysosomes, vacuoles, and the endoplasmic reticulum

The child shown in the figure below is not feeling well. Why does the poster say "No Antibiotics Please"?

His illness is caused by a virus.

A study conducted by the National Institutes of Health on the infectivity of methicillin-resistant Staphylococcus aureus (MRSA) stated their hypothesis as

MRSA bacteria lacking the ability to produce a protein (PSM) would be less deadly than those producing it

The _____ is the most prominent membrane-bound organelle in eukaryotic cells, and it houses most of a cell's DNA.

Nucleus

________ are the major lipids of plasma membranes.

Phospholipids

_______is used in all steps of protein synthesis and carries the genetic information of many viruses.

RNA

Which plant organelle is responsible for photosynthesis?

chloroplast

_______are tightly coiled bundles of DNA and protein found in the nucleus of most living cells.

chromosomes

The figure below shows a Paramecium, a single-celled freshwater protist. The hairlike structures visible on the Paramecium allow it to move. These structures are ________.

cilia

When mixed with water, phospholipids spontaneously form membranes because they ______.

have hydrophilic phosphate groups that are attracted to water and hydrophobic fatty acid tails that avoid water

The __________is the two-layered membrane that encases the nucleus of a eukaryotic cell, separating the nucleus from the cytoplasm.

nuclear envelope

A protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm is called a ________

nuclear pore

The round body that sits inside the nucleus of a eukaryotic cell and makes ribosomal subunits from proteins and ribosomal RNA is known as the ________

nucleolus

The concept of a membrane as a fluid mosaic reflects the ability of ______.

phospholipids and most proteins to drift about in the plane of the membrane

Which of the following is a function of the plasma membrane?

regulate the traffic of chemicals in and out of the cell

Examine the structures of the plant and animal cells below. Which of the following organelles connect(s) to the nuclear envelope?

the endoplasmic reticulum