12. Fill in the table below

12. Fill In The Table Below

Answers

Answer 1

Saturated fats are solid at room temperature. unsaturated fats are liquid at room temperature. Commonly saturated fats are found in animal foods and also in plant foods. Unsaturated fats are mostly found in plant foods. The bonds connecting in saturated fats are single bonds and in unsaturated fats are one or more double bonds.

What is saturated fats?

When the fatty acid chains in a fat have only single bonds, the fat is said to be saturated. Glycerides, a type of fat, are composed of two different kinds of smaller molecules: fatty acids, which each have a long linear or branched chain of carbon (C) atoms, and glycerol, which has a short backbone.

it is solid at room temperature because of it's molecular shape.

mostly found in animals fats.

What is unsaturated fats?

Chemical composition is a defining characteristic of unsaturated fats. They can be categorised as monounsaturated or polyunsaturated and are liquid or soft at room temperature (as in oils and spreads). Unsaturated fatty acids may have a variety of health advantages, but overall, they are better for you than saturated fats.

it is liquid at room temperature.

mostly found in plant fats .

Learn more about fats here :

https://brainly.com/question/7632072

#SPJ13


Related Questions

Select the plant cell's important sources of chemical energy transfer:

a. ATP
b. NADPH

Answers

In addition to ATP synthesis in the mitochondria, plants can also produce ATP in their chloroplasts during the light reactions of photosynthesis.

The two principal organelles in plant leaves that produce ATP are chloroplasts and mitochondria. Two different types of energy-carrier molecules, ATP and NADPH, store the solar energy in the light-dependent reactions. These molecules' stored energy is contained in the bond that binds one atom to the molecule. It is a phosphate atom for ATP and a hydrogen atom for NADPH. The light response of photosynthesis results in the production of ATP and NADPH. The biosynthetic pathway employs these. Additionally, they are employed in the Calvin cycle to lower carbon dioxide.

Learn more about mitochondria here-

https://brainly.com/question/10688306

#SPJ4

How are you likely to feel when your parasympathetic nervous system has been activated?.

Answers

Answer: Most likely, because you'd feel in your body.

Explanation: When the parasympathetic nervous system (PSNS) is activated, it slows our heart and breathing rates, lowers blood pressure and promotes digestion. Our body enters a state of relaxation, and this relaxation breeds recovery.

which characteristic makes fungi similar to plants

Answers

Like plant cells, fungal cells have a thick cell wall. The rigid layers of fungal cell walls contain complex polysaccharides called chitin and glucans. Chitin, also found in the exoskeleton of insects, gives structural strength to the cell walls of fungi.

Using the graph(s) in model 1 , determine the approximate average height of males and of females

Answers

Solving the sum of values in the data set number of items in the data set yields the mean of a set of values, often known as the average.

What is meant by Average?Taking the mean of the data yields the average of a set of data. Leveling the numbers until they are all the same yields the mean.Multiply the midpoint of each group by the total number of subjects in each group. The items from Step 2 are totaled. Subtract the total number of subjects from the total number of subjects. This is an approximate average.In layman's terms, an average is a single number chosen to represent a set of numbers, usually the sum of the numbers divided by the number of numbers in the set.

To learn more about Average refer to:

https://brainly.com/question/20118982

#SPJ10

12. What determines a protein's structure and function?

Answers

Each protein's 3D shape and function depend on its amino acid sequence. Nucleotides in gene sequences code amino acids.

What is protein?

Large biomolecules and macromolecules known as proteins are made up of one or more long chains of amino acid residues.

Proteins are the fundamental elements necessary for life. Protein can be found in each and every cell in the human body. A chain of amino acids constitutes the fundamental structure of proteins. In order for your body to be able to repair damaged cells and create new ones, you need to get enough protein in your diet.

They serve as the fundamental component of a variety of bodily structures and substances, including hair and skin, as well as enzymes, cytokines, and antibodies.

Learn more about proteins, here:

https://brainly.com/question/10945907

#SPJ1

Standard NCES.7.L.2.3- Jared has a genetic disorder. Which is the most likely reason Jared has the disorder?
Group of answer choices

Jared was exposed to chemical pollutants.

Jared has a poor diet and does not exercise.

Jared’s mother or father also has the disorder.

Jared attends school with another child who also has the disorder.

Answers

Answer: Jared’s mother or father also has the disorder.

Explanation: Genetic means coming from your ancestors DNA, so the most logical answer is Jared’s mother or father also has the disorder.

C: Jared's mother or father also has the disorder.

Identify the ways in which the work of franz boas challenged the concept of race.

a. By studying traits in immigrants,
b. Boas showed that racial types were not static and differed across different environments.
c. By studying traits in both parents and their children,
d. Boas showed that the phenotypic characteristics associated with race can change in a single generation.

Answers

All of the given answers, By studying traits in immigrants, Boas showed that racial types were not static and differed across different environments, traits in both parents and their children.

Despite sharing the same DNA, identical twins are not exactly same. Each twin is unique in terms of personality, skills, and likes and dislikes. Even now, a number of disorders, such as cancer, diabetes, autism, and schizophrenia, can affect one twin but not the other. Identical twins' variances are all caused by extrinsic causes rather than variations in their DNA.

Twin studies are frequently used by scientists to better understand how attributes are influenced by both the environment and genes. They contrast the traits of fraternal twins, who share half of their DNA with each other like siblings, and identical twins, who have the same DNA. If identical twin pairs exhibit a trait more frequently than fraternal twin pairs, it is likely to have an inherited component.

Learn more about traits here:

https://brainly.com/question/1463051

#SPJ4

an order is subdivided into several

Answers

An Order can be further divided into family .

In general class is divided into order , order to family and family to groups. Family occupies lower place in the taxonomic categories .example include Grasses belong to the order Poales and it belongs to one of its families, which is called Poaceae.

Taxonomy is the study of animal ,plant ,microorganism and human which help to classify them into further categories and study them with details .Other important example include human and whale they are two different identity but they are grouped under mammals and are taxonomically related . Taxonomy is based on Characterisation, Identification, Nomenclature, Classification.

To learn more about Taxonomy  , here

brainly.com/question/19184314

#SPJ1

In complex movements, muscles commonly work in groups rather than individually. The hamstrings flex the knee. Which muscles are antagonists to the hamstrings?.

Answers

The antagonist is the quadriceps. The quadriceps contract to extend the knee during the contact and recovery phase, while the hamstrings lengthen to allow movement.

Is the hamstring stretch antagonistic or agonistic?

When the knee extends, the hamstrings stretch, as well as the antagonists of this activity. When the knee bends, the hamstrings become the agonist muscle, and the quadriceps now become the antagonist.

The three hamstring muscles are as follows: Biceps femoris, located on the outside of your body. This hamstring's function is to flex your knee, extend your thigh at your hip, and rotate your lower leg from side to side when your knee is bent.

Therefore, In complex movements, muscles that are antagonists to the hamstrings are the quadriceps.

Learn more about muscles from the given link.

https://brainly.com/question/9883108

#SPJ4

may you define erosion deposition and weathering

Answers

Erosion is the washing away of the of the top layer of sand or rocks due to wind and water. Deposition is the settling down of the sand, soil or other granules carried away to a place due to wind and water. Weathering is the breakdown of rocks due to several reasons.

Erosion is the phenomenon of soil particles from one place to another. It is the major cause for the unrooting of trees and their falling off. It affects the ability of the soil to hold water and nutrients.

Weathering is the dissolution of the large solid rocks into small particles like soil or sand. Depending upon the agent causing weathering, it can be of three types: physical, chemical and biological.

To know more about weathering, here

brainly.com/question/14426457

#SPJ1

What happens within the cytoplasm of a cell?

O maintaining of a cell's shape and structure

O communication with other cells

O replication of DNA

O majority of metabolic activity

Answers

Answer:

A. Maintaining of a cells shape and structure,I believe

Explanation:

Answer: A. maintaining of a cell's shape and structure

examples of anabolic reactions include the synthesis of large from amino acid building blocks, and the synthesis of new dna strands from nucleic acid building blocks.

Answers

To create complex molecules from smaller ones, anabolic pathways need an energy input.

What constituent parts go towards the production of DNA?

Adenine, Cytosine, Guanine, and Thymine. These are the four chemical components that make up the DNA molecule. They are parts of the nucleic acid that gives DNA its tongue-twisting full name, deoxyribonucleic acid. A, C, G, and T.

Other examples include the creation of big proteins from amino acid-building pieces and the creation of new DNA strands from nucleic acid-building components.

Therefore anabolic processes include creating larger molecules.

Learn more about anabolic reactions from the given link.

https://brainly.com/question/17447614

#SPJ4

What was the effect on the environment of
banning chlorofluorocarbons?

Answers

Ozone layer preservation and a large decrease in global warming were both achieved by an international ban on ozone-depleting substances. The chlorofluorocarbons (CFCs) ozone-depleting compounds were outlawed globally in 1987, preventing a disastrous increase in the amount of ultraviolet radiation (UV) reaching the Earth's surface.

What kind of environmental impact do chlorofluorocarbons have?

Chlorofluorocarbons (CFCs) are a class of artificially produced, odorless compounds. CFCs have been prohibited since 1996 due to the harm they do to the ozone layer of the earth. The biodiversity of the world itself will suffer if the ozone layer is destroyed.

If CFCs had not been prohibited, what would have happened?

CFCs are potent greenhouse gases; according to US studies, if CFC use had continued unchecked, global temperature would have increased by 2°C by the year 2070. Extreme weather, including floods, droughts, hurricanes, and heatwaves, would have been fueled by this.

To learn more about global warming click on the link below:

https://brainly.com/question/8705135

#SPJ13

The centrally located area between the lungs contains?

Answers

The space in the middle, between the lungs and outside of it, is called the mediastinum.

The space in the middle between the lungs and outside of it is called the mediastinum. The heart, aorta, trachea, esophagus, thymus gland, bronchial tubes, and a large number of lymph nodes are all found within.)

The thoracic cavity's central compartment is called the mediastinum. It is an undelineated region that contains a group of thorax structures, including the heart and its vessels, the esophagus, the trachea, the phrenic and cardiac nerves, the thoracic duct, the thymus, and the central chest lymph nodes. It is surrounded by loose connective tissue.

Pleurae surround the mediastinum on the right and left, enclosing it within the thorax. It is surrounded by the lungs to the sides, the spine to the back, and the chest wall to the front. It connects the vertebral column behind the sternum in front. Except for the lungs, it contains all of the thoracic organs. It continues with the neck's loose connective tissue.

Learn more about Lungs here: https://brainly.com/question/13252600

#SPJ4

Which pieces of information about mitochondria is most useful as evidence for the endosymbiotic theory?

Answers

There is ample evidence that mitochondria have their own machinery for protein synthesis and contain DNA that is distinct from that of the cell nucleus.

The DNA of mitochondria and plasmids is circular double-stranded DNA in the form of plasmids, similar to that of bacteria. It is unbound by histones. Furthermore, many RNA and ribosome properties in eukaryotic cell mitochondria are similar to those of bacteria. However, plastid and mitochondrial DNA contain far fewer genes than nuclear DNA; nuclear genes encode the vast majority of mitochondrial and plastid proteins.

In addition to lacking histones, both mitochondria and chloroplasts have circular, single-stranded DNA. Prokaryotes are the only organisms that have circular, single-stranded DNA. These characteristics would allow mitochondria and chloroplasts to thrive on their own, lending credence to the endosymbiotic theory.

Learn more about mitochondria here:

https://brainly.com/question/10688306

#SPJ4

What would be the impact of a genetic mutation that resulted in the production of only fetal hemoglobin and no adult hemoglobin?.

Answers

The impact of genetic mutation that resulted in the production of only fetal hemoglobin and no adult hemoglobin will be that there will be no production of β-subunits.

Genetic mutation is the change in the sequence of the genes that change the effect of the proteins. The mutation can be caused due to deletions, addition, inversion, or duplication. There are also some mutations that do not cause any visible change and they are termed as silent mutations.

Fetal hemoglobin is a dominant form of hemoglobin present in the fetal stage as well as during the birth of the fully grown child. It is also 4 subunit structure like the adult hemoglobin. But unlike the adult hemoglobin, it has 2 α and 2 γ subunits, in place of β subunits.

To know more about fetal hemoglobin, here

brainly.com/question/16964787

#SPJ1

What groups has a series of similar segments that mak up most if its body?

Answers

Millipedes groups has a series of similar segments that mak up most if its body.

The split of some animal and plant body plans into a number of recurring segments is known as segmentation in biology. The segmentation of animal body plans is the main topic of this article, which uses the taxa Arthropoda, Chordata, and Annelida as examples. The segments created by these three groups are directed and defined by a "growth zone." All three of them use a development zone and have a broadly segmented body plan, although their methods for producing this patterning vary. Various creatures have different methods for body segmentation even within these groupings. To allow for free movement and the development of specific body components, the body plan must be segmented. Additionally, it enables certain people to regenerate.

learn more about segmentation here :

https://brainly.com/question/12728072

#SPJ4

if one were to attempt gene therapy, would a recombinant form of the insulin gene be needed?

Answers

If one were to attempt gene therapy, a recombinant form of insulin gene will not be needed.

In the field of science, gene therapy can be described as replacing a faulty gene with a new gene.

A recombinant form of insulin will not be needed for gene therapy because the insulin gene regulatory region will allow the expression of the insulin gene in the pancreas. If insulin were to be produced by any other cells of the body, then the insulin gene regulatory region for that cell of the body will be required.

To learn more about gene therapy, click here:

https://brainly.com/question/824754

#SPJ4

If the rate of CO2 is the same as the rate of O2, is photosynthesis and cellular respiration at equilibrium?

Answers

If the rate of [tex]CO_{2}[/tex] is the same as the rate of [tex]O_{2}[/tex], the photosynthesis and cellular respiration are said to be at equilibrium where they achieve the compensation point.

The point on the light curve when photosynthesis and respiration occur at the exact same rate is known as the (light) compensation point. The early mornings and late evenings are when this point is achieved. While photosynthesis is mostly dependent on the amount of sunlight, respiration is rather constant.

The point on the light curve when photosynthesis and respiration occur at the exact same rate is known as the compensation point. At this moment, the intake of [tex]CO_{2}[/tex] by photosynthesis routes and the respiratory release of [tex]CO_{2}[/tex] are perfectly matched, just as the uptake of [tex]O_{2}[/tex] by respiration and the photosynthetic release of [tex]O_{2}[/tex] are perfectly matched.

At this compensation point, the plant neither produces nor consumes biomass, and thus they are said to be at equilibrium.

To know more about respiration, refer to the following link:

https://brainly.com/question/14158795

#SPJ1

During what phase of the development of a neural network are thousands of examples presented to the neural network to create an refine the internal hidden layers?.

Answers

The reflection phase of the development of a neural network is where thousands of examples are presented to the neural network to create an refine the internal hidden layers.

What is Setback?

These are the events which delays the progress of something and in some cases, it reverses some strides or progress done by the individual. This can be encountered as a result of various types of factors and other parameters.

Reflection phase is where an individual thinks deeply about certain events and thousands of examples presented to the neural network to create an refine the internal hidden layers.

This phase helps in deciphering the next line of action which is beneficial for the individual and is therefore the reason why it was chosen as the correct choice.

Read more about Reflection here  https://brainly.com/question/17190127

#SPJ1

Why do muscles need both an origin and an insertion point to properly function?

Answers

The origin and insertion points of skeletal muscles allow force to be exerted that allows movement of the skeleton. Skeletal movement is a form of lever mechanics with the position of origin and insertion of the muscle allowing for differences in force, velocity, and directionality

which term describes a band of fibers that hold structures together abnormally? a. contracture b. spasm c. adhesion d. singultus

Answers

Correct answer is option c. adhension

What is adhension?

Cohesion describes how similar or identical particles or surfaces prefer to stick together, whereas adhesion describes how different particles or surfaces tend to stick together.

There are various subtypes of forces that lead to adhesion and cohesion. Chemical adhesion, dispersive adhesion, and diffusive adhesion are the three intermolecular forces that determine how different kinds of stickers and sticky tape work. These intermolecular forces have cumulative magnitudes, but there are also some emergent mechanical effects.

Water Molecule Adhesion

Water frequently displays the adhesion property. This is due to the fact that water's stickiness enables it to "stick" to several surfaces and things. The easiest way to describe water's capacity to adhere to other surfaces is that it can do so by forging tenuous surface bonds. Numerous actions and reactions of water in both the lab and in nature can be attributed to its adhesion property.

Learn more about adhension from given link

https://brainly.com/question/1214644

#SPJ4

what enables the copied chromosomes to separate during binary fission?

Answers

In bacteria, a mechanism known as binary fission separates the replicated chromosomes to do this. Cells split into two new daughter cells by a process called binary fission.

There are exactly as many chromosomes in each daughter cell as in the parent cell. Bacteria, algae, and protozoans all use the binary fission mechanism. It stands out for having a straightforward cell division process. Binary fission is the mechanism responsible for this.

A chromosome is a lengthy DNA molecule that contains all or a portion of the genetic code for an organism. The majority of eukaryotic chromosomes contain packing proteins called histones that help chaperone proteins attach to and condense the DNA molecule in order to preserve the integrity of the chromosome.

Learn more about  Binary fission here

https://brainly.com/question/7639952

#SPJ4

Standard NCES.7.L.1.3 - The structures in the bodies of many organisms have levels of organization that help the body to carry out life processes. Which list correctly shows how these levels are organized from the simplest to the most complex?
Group of answer choices

tissue, cell, organ, organ system

organ, cell, organ system, tissue

cell, tissue, organ, organ system

organ system, tissue, organ, cell

Answers

Answer:

Cell, tissue, organ, organ system.

Explanation:

The major levels of organization in the body, from the simplest to the most complex are: atoms, molecules, organelles, cells, tissues, organs, organ systems, and the human organism.

During sexual reproduction two sex cells fuse to make a fertilized cell with one set of chromosomes what must be true about the number of chromosomes in sex cell?

Answers

Answer:both genders have the same amount of chromosomes

Explanation:Sexual reproduction is the process in which male and female gametes fuse to form a zygote. The zygote consists of a complete set of chromosomes, which 23 pairs or 46 chromosomes.

Sexual reproduction is the process in which two sex cells fuse to form the fertilized cell, usually known as zygote. The sex cells are egg or ova and sperms for females and males, respectively.

The number of chromosomes in each sex cell and fertilised cell will be:

The sex cells are formed by the meiotic division, such that each ova and sperm will consist of 23 chromosomes.

These haploid cells fuse to form a diploid zygote, which will have the same number of chromosomes as parent cell. The umber of chromosomes in the fertilised egg will be 46.

Therefore, the number of chromosome in each sex cell is 23, which fuses to form a diploid fertilised cell having 46 chromosomes.

what is an ecosystem ​

Answers

An ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life.

Answer:

An ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life.

Explanation:

Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. Biotic factors include plants, animals, and other organisms.

According to the segment, what percent of the world’s freshwater supply is used for agricultural purposes?.

Answers

Over 70% of the world’s freshwater supply is used for agricultural purposes.

all the following are functions of the skeleton except . all the following are functions of the skeleton except . site of red blood cell formation production of melanin attachment for muscles storage of lipids

Answers

Answer:

Production of melanin

Explanation:

Melanin is a product of a chemical process that takes place in the skin and hair follicles so it is not produced by the skeleton.

How is voice timbre inherited?​

Answers

Explanation:

How is voice timbre inherited

Is Your Vocal Ability And Range Influenced By Genetics? - Yona Marie Your vocal talent abilities may and may not be affected by genetics. On the one hand, your vocal tone, also known as timbre, can also be traced back to how your vocal cords and larynx muscles are shaped, with each person having a unique voice box that could be influenced by genetics.

A. Using information from data in Graph 2, describe the relationship between marine iguana body length and reproductive success for male iguanas on Genovesa and Santa Fe.

Answers

The marine iguana evolved from the land iguana which was introduced to the Galapagos Islands and adapted to life in the sea to survive on the islands.

The claws are long and sharp enough to grab onto coastal rocks or in strong currents. After venturing into the cold Galapagos waters they become dark gray in color to better absorb sunlight. increase.

This variation in marine iguana body size from island to island is due to the amount of food available which depends on sea temperature and algae growth. Marine iguanas are sexually dimorphic with adult males on average being considerably longer and weighing about twice as much as adult females.

Learn more about The marine iguana here:-https://brainly.com/question/23557942

#SPJ1

Other Questions
LT.2C - COMPOUNDS - QUESTION 1Which of the following Lewis structures is invalid (because it breaksthe octet rule, or because it uses too many/too few electrons)?HHP-HI-U::IF-F:HHHa.a.b..C.d.. how can I differentiate a ketone from aldehyde yet they are both carbonyls class What were American citizens doing before Prohibition started and what causedProhibition or the 18th amendment to be put into place? HELP ME PLEASE Ramiro got a job through the McGovern Employment Agency. The job pays $59400 per year, and the agency fee is equal to 25% of one month's pay How much must Ramir0 pay the agency? Round to the nearest cent. There are 12 months in a year. Input the numbers only -do not insert a dollar sign. Previous o new data to save astchegked at 2:0am Submit Q a nurse is assessing a client with angina who has received diltiazem. which finding should the nurse prioritize and notify the health care provider for further instructions? The formulas below are the cost and revenue functions for a company that manufactures and sells small radios.C(x)=90,000 +42x and R(x) = 47xa. Use the formulas shown to write the company's profit function, P, from producing and selling x radios.b. Find the company's profit if 23,000 radios are produced and sold.*** PLEASE HELP ASAP. Rabbits are very popular domesticated animals, so popular that there are over 300 breeds of domesticated rabbits in the world. You attend a rabbit show and notice that all of the breeds vary in many characteristics, such as size, color, and fur length. You notice that there is weight information on the cages of all rabbit individuals at the show and decide to jot down data for two specific rabbit breeds (in pounds):Breed A: 10, 8, 7, 10, 9, 9, 10, 9Breed B: 10, 12, 14, 13, 10, 15, 11, 12In three to five sentences, 1) calculate the average weights of the two rabbit breed groups, 2) describe some factors that could contribute to the different weights seen within breeds, and 3) describe how you would track and find the growth rate of the two rabbit breeds during an investigation. What is the value of the expression?Enter your answer as a simplified mixed number Using the selected country Haiti , identify the current legal system (civil, common, religious, or mixed). Describe the influence that colonization had on the formation of the current legal system. pls help ill give brainliest!the land area of adeline's house is 235 square meters. what is this in square feet? explain and answer with solution. Select the correct answer. When a substance changes from one phase to another, which of the following events occurs? A. The substance loses or gains heat. B. The average kinetic energy of the substance changes. C. The temperature of the substance changes. D. The molecular motion of the substance changes. The tangent line to the graph of y=h(x) at the point (-1,4) passes through the point (3,6). Find h(-1) and h'(-1). Find the EQUATION OF THE TANGENT to g(x)=(x-4)^2 at its y-intercept. Please use an appropriate limit, much appreciated! Garrett is a member of The Mighty Manatees, an outdoor swim team. Every practice, his coach tells him to swim a target number of laps. One day, Garrett swims 31 laps before practice is canceled due to a thunderstorm. Garrett still has 29 laps left to reach his target number. The speaker's central message to her audience is mainly.A to highlight, in spite of recent advances, that women remain second-class citizens everywhere in the worldB. that young women in the 21st century should speak out for justice and follow their heartsC. that we should celebrate how women have finally completed the long road to gender equalityD. that no one should join any revolution or movement that isn't fun Help!! What would K be? What causes the formation of acetone, which eventually leaves the body through the lungs, causing breath with a fruity smell?. How did Muhammad, the founder of Islam, see himself in relation to Christianity and Judaism?Muhammad believed he was a prophet like Abraham, Moses and Jesus of the Jewish and Christian faiths.Muhammad believed that God was establishing a new religion upon the earth through him.Muhammad believed that only Arabs would become Muslims and be accepted into heaven by God.Muhammad believed that God had been defeated by Satan and had ordered a new faith. Emily is standing 24 feet away from a light pole. The distance between Emily to a point of tangency on the pole is 12 feet. What is the radius of the light pole?Note : In the figure distance between Emily and the point of tangency is marked as 24 ft instead of 12. Sort the phrases into the appropriate bins depending on whether they are true only for channels, true only for carrier proteins, or true for both channels and carriers. a. provide a hydrophilic path across the membrane b. provide a continuous path across the membrane c. are integral membrane proteins d. transport solutes down a concentration or electrochemical gradient e. allow water molecules and small ions to flow quickly across the membrane f. transport primarily small polar organic molecules g. undergo a change in shape to transport solutes across the membrane 1. only channels 2. only carriers 3. both channels and carriers