Biology Ch. 7

phagocytosis

"cell eating" Extensions of cytoplasm surround a particle and package it within a food vacuole. The cell then engulfs it.

organ system

A group of organs that work together to perform a specific function

tissue

A group of similar cells that perform a particular function.

cytoskeleton

A network of protein filaments that helps the cell to maintain its shape and is also involved in movement.

unicellular

A single-celled organism is also called a _____________ organism.

cell membrane

All cells are surrounded by a thin, flexible barrier known as the _______________ which regulates what enters and leaves the cell and also provides protection and support

both

Are mitochondria found in plant cells, animal cells, or both?

ancient prokaryotes

Biologist, Lynn Margulis, has suggested that mitochondria and chloroplasts are descendants of what kind of organisms?

cell specialization

Cells throughout an organism can develop in different ways to perform different tasks

nuclear envelope

Composed of two membranes which surround the nucleus

it forms a vacuole

During endocytosis, what happens to the pocket in the cell membrane when it breaks loose from the membrane?

bacteria

Example of Prokaryote

plants, animals, fungi and protists

Examples of Eukaryotes

Golgi Apparatus

Function of this organelle is to modify, sort andpackage proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell

chromatin

Granular material that can be seen in the nucleus and consists of DNA bound to protein

organ

Groups of tissues that work together to perform a specific function.

Anton van Leeuwenhoek

He was one of the first to see tiny living organisms in pond water

microtubules

Hollow structures mad up of proteins known as tubulins which play critical roles in maintaining cell shape.

in a cell theory

How did Rudolph Vircho Summarize his years of work?

pumps excess water out of the cell

How does the contractile vacuole in a paramecium help maintain homeostasis?

permeable

If a substance is able to diffuse across a membrane, the membrane is said to be __________ to it.

plants

In what organisms are cell walls found?

organelle

Little organs

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

chloroplasts

Organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis

mitochondria

Organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use

diffusion

Process by which molecules move from an area where there are more concentrated ta an area where they are less concentrated

vacuoles

Saclike structures that store materials such as water, salts, proteins, and carbohydrates

endoplasmic reticulum

Site where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell

nucleolus

Small dense region where the assembly of ribosomes begins

Lysosomes

Small organelles filled with enzymes

ribosomes

Small particles of RNA and protein which use energy from sunlight to make energy-rich food

selectively permeable

Some substances can pass across them and others cannot

lipid bilayer

The core of nearly all cell membranes is a double-layered sheet called a ______________.

osmosis

The diffusion of water through a selectively permeable membrane.

active transport

The energy-requiring process that moves material across a cell membrane against a concentration difference

exocytosis

The membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell.

cytoplasm

The portion of the cell outside the nucleus

endocytosis

The process of taking material into the cell by means of infoldings, or pockets, of the cell membrane

If a solution is hypertonic

The solution is above strength in solute

If a solution is hypotonic

The solution is below strength in solute

cell

The structure that makes up every living thing

pinocytosis

Tiny pockets form along the cell membrane, fill with liquid, and pinch off to form vacuoles within the cell

fibers of carbohydrate and protein

What are most plant cell walls made from?

muscle, epithelial, nervous, connective

What are the four main types of tissue in most animals?

cells, tissues, organs and organ systems

What are the levels of orgnaization in a multicellular organism?

a) all living things are made of cells b) cells are the basic unit of structure and function c) new cells are made of existing cells

What are the three concepts that make up the cell theory?

empty chambers

What did a thin slice of cork seem like to Robert Hooke when he observed it through a microscope?

all plants are made of cells

What did the German botanist Matthias Schleiden conclude?

mass/volume

What is the concentration of a solution?

rough ER has ribosomes attached to it

What is the difference between rough ER and smooth ER?

controls the cell

What is the function of the nucleus?

the pressure makes it possible for plants to support heavy structures such as leaves and flowers

What is the role of the central vacuole in plants?

chromosomes

When a cell divides, chromatin condenses to form__________, threadlike structures which contain the genetic information that is passed fro one generatio of cells to the next

equilibrium

When the concentration of the solute is the same throughout a system

in plant cells

Where are chloroplasts found?

wavelengths of electrons are much shorter than those of light

Why are electron microscopes capable of revealing details much smaller than those seen through light microscopes?

nucleus (pl. nuclei)

a large membrane-enclosed structure that contains the cell's genetic material in the form of DNA

membrane

a thin layer of material that serves as a covering or lining

Function of lysosomes

a) digestion or break down of lipids, carbohydrates, and proteins b) breaking down organelles that have outlived their usefulness c) removing junk that might clutter up the cell

Characteristics of Eukaryotes

a) larger and more complex than prokaryotic cells b) some are single-celled organisms c) others form large, multicellular organisms

Characteristics of Prokaryotes

a) smaller and simpler than eucaryotes b) they can grow, reproduce, and respond to the environment, c) some can even move

hypertonic

above strength

hypotonic

below strength

centrioles

located near the nucleus and help to organize cell division (not found in plant cells)

eukaryotes

organisms whose cells contain nuclei

prokaryotes

organisms whose cells lack nuclei

isotonic

same strength

If two solutions are isotonic

the solutions are the same strength

microfilaments

threadlike structures made of a protein called actin which form extensive networks and produce a tough, flexible framework that supports the cell.

scanning electron microscope

using a pencillike beam of electrons scanned over the surface of a specimen to produce three-dimensional images of cells