Honors Biology 9 Cell Structure/Function Study Guide

Cell/Plasma Membrane

a thin layer of lipids and proteins that separates the cell’s contents from its surrounding environment

phospholipid bilayer

The cell membrane consists of a __________ with embedded proteins that encloses the cytoplasm of a cell. The selective permeability of the cell membrane is caused by the interaction of phospholipids with water.

loving

A hydrophilic “water-______” phosphate-based polar head-easily dissolves in water.

fearing

A hydrophobic “water-______” non-polar lipid tail which does not dissolve in water.

Mosaic

refers to the fluid model mosaic

Fluid

 refers to the environment both inside and outside cells, maintaining cell function and the transport of molecules and signals

Model

used to understand cellular processes in a non microscopic way

Fluid model mosaic

Comparing the structure of the cell membrane to a mosaic

Selective

The process where specific traits or characteristics are favored for survival and reproduction

Permeability

the trait of letting a substance or substances pass through a barrier or cell membrane

Selective permeability

 the trait of letting some substances through while preventing other substances from entering into a barrier or cell membrane

Laterally

to move from side to side, or in a straight line

Immobile

something incapable of moving

Rigid

A structure that cannot move

static

The action of not moving

They can move laterally within the membrane

According to the fluid mosaic model, which of the following best describes the movement of phospholipids in the cell membrane?

Passive Transport

the movement of substances across a cell membrane without the input of the cell’s energy. Passive transport includes both diffusion and osmosis.

Diffusion

the movement of a substance from an area of high concentration to an area of low concentration, known as movement down a concentration gradient. Diffusion is caused by the random motion of particles. If diffusion is allowed to continue equilibrium results.

Osmosis

the diffusion of water across a selectively permeable membrane.

Hypotonic Solution

having the lower osmotic pressure of two solutions. If a cell were placed in a hypotonic solution the concentration of solutes would be lower outside of the cell than inside the cytoplasm of the cell.

Isotonic Solution

a solution of equal osmotic pressure.  In an isotonic solution concentration of solutes outside the cell is equal to that inside the cell.

Hypertonic Solution

having the higher osmotic pressure of two solutions. In a hypertonic solution the concentration of solutes is higher outside the cell than in the cytoplasm of the cell.

simple diffusion

When the concentration of oxygen is greater outside a cell than inside the cell, oxygen will move into the cell without the assistance of proteins or additional energy. This movement of oxygen is an example of what process?

Active transport

is a cellular process that uses energy, often in the form of ATP, to move molecules or ions across a cell membrane against their concentration gradient (from low to high concentration). Active transport includes facilitated transport.

Facilitated Transport

a type of passive transport in which specific substances (such as amino acids and sugars) are transported through proteins down their concentration gradient.

Sodium-Potassium Pump

a carrier protein transports sodium ions out of a cell and potassium ions into the cell. This pump actively transports both sodium and potassium against their concentration gradients.

prevents the toxic build-up of sodium ions that have diffused into the cell through ion channels and helps maintain the concentration gradients of sodium and potassium ions across the cell membrane, which facilitates the transport of other substances.

The sodium-potassium pump . . . (purpose)

ATP

The sodium-potassium pump in a cell membrane moves particles from an area of low concentration to an area of high

concentration. What directly supplies the energy for the sodium-potassium pump?

Endocytosis

the movement of a substance into a cell by a vesicle

Phagocytosis

“cell eating” is the ingestion of solid particles by endocytosis. The cytoplasmic membrane invaginates and pinches off placing the particle in a phagocytic vacuole. The phagocytic vacuole then fuses with lysosomes and the material is degraded

Pinocytosis

“cell drinking” is when a cell takes in liquids

Exocytosis

the movement of a substance out of a cell by a vesicle

Cell Cycle

repeating phases of cellular growth and cellular division which occur in eukaryotic cells. Major phases of the cell cycle are interphase, mitosis, and cytokinesis

Interphase

 the phase that occurs between periods of cell division (mitosis).  It is the longest part of the cell cycle and occurs in three different stages called G1, S, & G2

G1 (Interphase)

period of growth during which the cell increases in size as well as performs its specialized functions (cardiac cells pump blood via the heart, skeletal muscle cells move the body, etc.)

S (Interphase)

 period of synthesis (copying) of DNA. Also called DNA Replication. After replication, there are four copies of each gene. Genes will pair together to form tetrads of sister chromatids.

G2 (Interphase)

the cell prepares for division by doubling the number of organelles and cell structures so they can be provided to the two daughter cells after mitosis. Specialized organelles called centrioles form spindle fibers which will divide chromosomes during cell division

Mitosis

a form of cellular division that produces two identical daughter cells with the same number and kind of chromosomes as the parent cell

Cytokinesis

Cytoplasm of cell divides in half Cell membrane grows to enclose each cell

Prophase

1. Chromatin condenses into chromosomes

2. Nuclear membrane dissolves

3. Centrioles migrate to poles

4. Spindle forms

Metaphase

1. Chromosomes align along middle of the cell (metaphase plate)

2. Spindle fibers attach chromatids to opposite poles of cell

Anaphase

1. Chromatids are pulled to poles as spindle fibers shorten.

2. Chromatids are split to become two identical sets of daughter chromosomes.

Telophase

1. Nuclear envelope forms

2. Chromosomes uncoil

3. Mitotic Spindle dissolves

4. Cytokinesis begins along a cleavage furrow

mitosis and cytokinesis

Spiders grow until they reach adulthood. Which processes lead directly to growth by increasing the number of cells the spiders have?

Mitosis - this because it produces new cells to replace old cells

A male anglerfish attaches to a female anglerfish using his teeth. When the male attaches to the female, some of the female’s cells are damaged. What process replaces the damaged cells of the female anglerfish?

Meiosis

a form of cellular division in which a cell divides to form four haploid daughter cells. These haploid cells have only one copy of each chromosome and are called gametes (sperm and egg). Gametes can fuse together through sexual reproduction to form a diploid offspring with two copies of every chromosome

Chromosome

a structure made of DNA on which genes are located. DNA condenses from chromatin into chromosomes before meiosis.

Chromatin

a thin, tangled bundle of many strands of DNA found in the nucleus during interphase.

Centromere

 the point where sister chromatids are joined

Sister Chromatids

identical copies of genetic material attached at centromere

Homologous Chromosomes

pairs of Chromosomes that are similar in size, shape, and genes

The unfertilized egg joins with a male gamete. -an egg has ½ the number of chromosomes & a sperm has ½ the number so when they fuse during sexual reproduction they combine to make the full number of gametes the new baby will have

An unfertilized egg from the European frog Rana esculenta has 13 chromosomes. A zygote of this species has 26 chromosomes. What causes the increase in chromosome number?

The zygote has three copies of chromosome 21. - the baby (zygote) should have 2 copies (one from mom one from dad) but if meiosis doesn’t work correctly a sperm or egg cell can end up with both copies (both from mom and one from dad, or both from dad and one from mom = 3)

A human gamete typically contains 23 chromosomes. Two human gametes combine to produce a zygote. Which of the following is the best evidence that an error occurred during the formation of one of these gametes?

Haploid

a cell having one set of chromosomes. A single haploid cell forms a gamete (sex cell) such as sperm or egg. Also called 1n because they only have 1 set of chromosomes.

Diploid

a cell having two sets of chromosomes. Diploid cells are somatic cells (body cells). Diploid cells often specialize to perform different functions of life. Diploid cells are called 2n because they have 2 sets of chromosomes.

Gamete

reproductive cells such as sperm or egg, they are haploid cells that go through sexual reproduction by fusing with another haploid cell to form a fertilized egg

Zygote

a fertilized egg formed from the fusion of two haploid cells such as sperm and egg

Fertilization

the term for the fusion of two haploid gametes to form a diploid zygote (a fertilized egg)

Meiosis is a method to maintain chromosome number from generation to generation. What does that statement mean?

It means that meiosis keeps the same number of chromosomes from generation to generation because the two sets of parent chromosomes mix but still create the same amount of chromosomes

How does meiosis and sexual reproduction increase diversity?

It leads to unique orders of genes in gametes and causes more variation in organisms.

What is a function of the endoplasmic reticulum?

Intracellular Digestion

What structure is responsible for packaging proteins for transport?

Golgi Complex

What describes the function of the vacuole?

Storage

Cellular respiration; glucose; energy; chemical; ATP

Through the process of ______, the molecules of _______ are broken down and _______ is released. The _______ energy released is stored in molecules of _______ and is used for cellular processes.

Eukaryotic

Contain an enclosed nucleus and membrane bound organelles. Plants and animals are made of these cells

Prokaryotic

A single-celled organism that lacks a nucleus and other membrane-bound organelles. These cells make up bacteria

Characteristic of Prokaryotic cells only

single celled organism, no nucleus and no membrane bound organelles, microscopic, very variable

Characteristics eukaryotic and prokaryotic cells share

Make up all life, both are cell types

Characteristics of eukaryotic cells only

make up plants and animals, contain membrane bound organelles, contains an enclosed nucleus

The functions of life can categorized as. . .

living things need energy, living things maintain homeostasis, living things respond to their environment, living things adapt and evolve, living things reproduce

What organelle can conduct photosynthesis?

Chloroplast

What pigment is found within the chloroplast?

Chlorophyll

Define photosynthesis

Photosynthesis is the process where plants convert light energy, H2O, and CO2 into glucose and release oxygen

What is the function of the mitochondria?

It generates the chemical energy needed to power the cell's biochemical reactions through a process called cellular respiration

What is homeostasis?

the process by which an organism (or cell) maintains balance within its body despite changing external environmental conditions

The cell membrane is semipermeable which means . . .

it allows some substances to pass into the cell but blocks others

What structure helps a cell maintain homeostasis?

cell membrane

True or False, both prokaryotic and eukaryotic cells have a cell membrane

true

What compounds does a cell membrane block?

Poisons and invading pathogens

What compounds does a cell membrane let into the cell?

Glucose

Cell wall

Lysosomes. . .

contain digestive enzymes that break down and digest cellular debris

Vacuoles. . .

are filled with digested food and waste material that will be released from the cell

central vacuole

Plant cells have a ______ that is filled with debris waiting to be released from the cell

How do lysosomes help the cell maintain homeostasis

They break down waste for the cells

nucleus

The _____ is a membrane-bound organelle that houses the cell's DNA

The smooth endoplasmic reticulum . . .

detoxifies poisons, alcohol, and drugs.

The rough endoplasmic reticulum . . .

is covered with organelles called ribosomes

ribosomes. . .

conduct protein synthesis

The Golgi apparatus. . .

either stores proteins until they are needed or packages them so they can be transported outside the cell for use in other parts of the body